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6  </HEAD>  <title>What is Free Software?
7  <BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#1F00FF" ALINK="#FF0000" VLINK="#9900DD">  - GNU Project - Free Software Foundation</title>
8  <H3>The Free Software Definition</H3>  <style type="text/css" media="print,screen"><!--
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13    <meta http-equiv="Keywords" content="GNU, FSF, Free Software Foundation, Linux, Emacs, GCC, Unix, Free Software, Operating System, GNU Kernel, HURD, GNU HURD, Hurd" />
14  [  <meta http-equiv="Description" content="Since 1983, developing the free Unix style operating system GNU, so that computer users can have the freedom to share and improve the software they use." />
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18  | <A HREF="/philosophy/free-sw.cs.html">Czech</A>  <!--GNUN: OUT-OF-DATE NOTICE-->
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20  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  <div class="article reduced-width">
21  | <A HREF="/philosophy/free-sw.html">English</A>  <h2>What is Free Software?</h2>
22  | <A HREF="/philosophy/free-sw.fr.html">French</A>  <div class="thin"></div>
23  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  
24  | <A HREF="/philosophy/free-sw.de.html">German</A>  <div class="important">
25  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  <p>
26  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  &ldquo;Free software&rdquo; means software that respects users'
27  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  freedom and community.  Roughly, it means that <b>the users have the
28  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  freedom to run, copy, distribute, study, change and improve the
29  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  software</b>.  Thus, &ldquo;free software&rdquo; is a matter of
30  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  liberty, not price.  To understand the concept, you should think of
31  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  &ldquo;free&rdquo; as in &ldquo;free speech,&rdquo; not as in
32  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  &ldquo;free beer.&rdquo;  We sometimes call it &ldquo;libre
33  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  software,&rdquo; borrowing the French or Spanish word for
34  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  &ldquo;free&rdquo; as in freedom, to show we do not mean the software
35  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>  is gratis.
36  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  </p>
37  | <A HREF="/philosophy/free-sw.sv.html">Swedish</A>    
38  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  <p>
39  <!-- Please keep this list alphabetical -->  You may have paid money to get copies of a free program, or you may
40  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  have obtained copies at no charge.  But regardless of how you got your
41  ]  copies, you always have the freedom to copy and change the software,
42  <P>  even to <a href="/philosophy/selling.html">sell copies</a>.
43    </p>
44  We maintain this free software definition to show clearly what must be  </div>
45  true about a particular software program for it to be considered  
46  free software.  <p>
47    We campaign for these freedoms because everyone deserves them.  With
48  <P>  these freedoms, the users (both individually and collectively) control
49    the program and what it does for them.  When users don't control the
50  ``Free software'' is a matter of liberty, not price.  To understand the  program, we call it a &ldquo;nonfree&rdquo; or
51  concept, you should think of ``free'' as in ``free speech,'' not as in  &ldquo;proprietary&rdquo; program.  The nonfree program controls the
52  ``free beer.''  users, and the developer controls the program; this makes the
53  <P>  program <a href="/philosophy/free-software-even-more-important.html">
54  Free software is a matter of the users' freedom to run, copy,  an instrument of unjust power</a>.
55  distribute, study, change and improve the software.  More precisely,  </p>
56  it refers to four kinds of freedom, for the users of the software:  
57  <P>  <p>
58    &ldquo;Open source&rdquo; is something different: it has a very
59  <UL>  different philosophy based on different values.  Its practical
60    <LI>The freedom to run the program, for any purpose (freedom 0).  definition is different too, but nearly all open source programs are
61    <LI>The freedom to study how the program works, and adapt it to your needs  in fact free.  We explain the
62        (freedom 1).   Access to the source code is a precondition for this.  difference in <a href="/philosophy/open-source-misses-the-point.html">
63    <LI>The freedom to redistribute copies so you can help your neighbor  Why &ldquo;Open Source&rdquo; misses the point of Free Software</a>.
64    </p>
65    
66    <div class="toc">
67    <hr class="no-display" />
68    <h3 class="no-display">Table of contents</h3>
69    <ul>
70     <li><a href="#fs-definition">The Free Software Definition</a>
71      <ul>
72       <li><a href="#four-freedoms">The four essential freedoms</a></li>
73       <li><a href="#selling">Free software <em>can</em> be commercial</a></li>
74      </ul>
75     </li>
76     <li><a href="#clarifying">Clarifying the Boundary Between Free and Nonfree</a>
77      <ul>
78       <li><a href="#run-the-program">The freedom to run the program as you
79         wish</a></li>
80       <li><a href="#make-changes">The freedom to study the source code and make
81         changes</a></li>
82       <li><a href="#redistribute">The freedom to redistribute if you wish:
83         basic requirements</a></li>
84       <li><a href="#copyleft">Copyleft</a></li>
85       <li><a href="#packaging">Rules about packaging and distribution
86         details</a></li>
87       <li><a href="#exportcontrol">Export regulations</a></li>
88       <li><a href="#legal-details">Legal considerations</a></li>
89       <li><a href="#contracts">Contract-based licenses</a></li>
90      </ul>
91     </li>
92     <li><a href="#in-practice">The Free Software Definition in Practice</a>
93      <ul>
94       <li><a href="#interpretation">How we interpret these criteria</a></li>
95       <li><a href="#get-help">Get help with free licenses</a></li>
96       <li><a href="#terminology">Use the right words when talking about free
97         software</a></li>
98      </ul>
99     </li>
100     <li><a href="#beyond-software">Beyond Software</a></li>
101     <li><a href="#History">History</a></li>
102    </ul>
103    </div>
104    
105    <div class="edu-note" id="fsf-licensing" role="complementary">
106    <p style="font-size:80%">
107    Have a question about free software licensing not answered here?
108    See our other <a href="http://www.fsf.org/licensing">licensing resources</a>,
109    and if necessary contact the FSF Compliance Lab
110    at <a href="mailto:licensing@fsf.org">licensing@fsf.org</a>.</p>
111    <hr class="no-display" />
112    </div>
113    
114    
115    <h3 id="fs-definition">The Free Software Definition</h3>
116    
117    <p>
118    The free software definition presents the criteria for whether a
119    particular software program qualifies as free software.  From time to
120    time we revise this definition, to clarify it or to resolve questions
121    about subtle issues.  See the <a href="#History">History section</a>
122    below for a list of changes that affect the definition of free
123    software.
124    </p>
125    
126    <h4 id="four-freedoms">The four essential freedoms</h4>
127    <p>
128    A program is free software if the program's users have the
129    four essential freedoms: <a href="#f1">[1]</a>
130    </p>
131    
132    <ul class="important">
133      <li>The freedom to run the program as you wish,
134          for any purpose (freedom 0).</li>
135      <li>The freedom to study how the program works, and change it so it
136          does your computing as you wish (freedom 1). Access to the source
137          code is a precondition for this.
138      </li>
139      <li>The freedom to redistribute copies so you can help others
140        (freedom 2).        (freedom 2).
141    <LI>The freedom to improve the program, and release your improvements    </li>
142       to the public, so that the whole community benefits    <li>The freedom to distribute copies of your modified versions
143        (freedom 3).   Access to the source code is a precondition for this.        to others (freedom 3).  By doing this you can give the whole
144  </UL>        community a chance to benefit from your changes.
145          Access to the source code is a precondition for this.
146  <P>    </li>
147  A program is free software if users have all of these freedoms.  </ul>
148  Thus, you should be free to redistribute copies, either with or  
149  without modifications, either gratis or charging a fee for  <p>
150  distribution, to <A HREF="#exportcontrol">anyone anywhere</A>.  Being  A program is free software if it gives users adequately all of these
151  free to do these things means (among other things) that you do not  freedoms.  Otherwise, it is nonfree.  While we can distinguish various
152  have to ask or pay for permission.  nonfree distribution schemes in terms of how far they fall short of
153    being free, we consider them all equally unethical.</p>
154    
155    <p>In any given scenario, these freedoms must apply to whatever code
156    we plan to make use of, or lead others to make use of.  For instance,
157    consider a program A which automatically launches a program B to
158    handle some cases.  If we plan to distribute A as it stands, that
159    implies users will need B, so we need to judge whether both A and B
160    are free.  However, if we plan to modify A so that it doesn't use B,
161    only A needs to be free; B is not pertinent to that plan.</p>
162    
163    
164    <h4 id="selling">Free software <em>can</em> be commercial</h4>
165    
166    <p>
167    &ldquo;Free software&rdquo; does not mean &ldquo;noncommercial.&rdquo;
168    On the contrary, a free program must be available for commercial use,
169    commercial development, and commercial distribution.  This policy is
170    of fundamental importance&mdash;without this, free software could not
171    achieve its aims.
172    </p>
173    
174    <p>
175    We want to invite everyone to use the GNU system, including businesses
176    and their workers.  That requires allowing commercial use.  We hope
177    that free replacement programs will supplant comparable proprietary
178    programs, but they can't do that if businesses are forbidden to use
179    them.  We want commercial products that contain software to include
180    the GNU system, and that would constitute commercial distribution for
181    a price.  Commercial development of free software is no longer
182    unusual; such free commercial software is very important.  Paid,
183    professional support for free software fills an important need.
184    </p>
185    
186    <p>
187    Thus, to exclude commercial use, commercial development or commercial
188    distribution would hobble the free software community and obstruct its
189    path to success.  We must conclude that a program licensed with such
190    restrictions does not qualify as free software.
191    </p>
192    
193    <p>
194    A free program must offer the four freedoms to any would-be user that
195    obtains a copy of the software, who has complied thus far with the
196    conditions of the free license covering the software in any previous
197    distribution of it.  Putting some of the freedoms off limits to some
198    users, or requiring that users pay, in money or in kind, to exercise
199    them, is tantamount to not granting the freedoms in question, and thus
200    renders the program nonfree.
201    </p>
202    
203    
204    <h3 id="clarifying">Clarifying the Boundary Between Free and Nonfree</h3>
205    
206    <p>In the rest of this article we explain more precisely how far the
207    various freedoms need to extend, on various issues, in order for a
208    program to be free.</p>
209    
210    <h4 id="run-the-program">The freedom to run the program as you wish</h4>
211    
212    <p>
213    The freedom to run the program means the freedom for any kind of person
214    or organization to use it on any kind of computer system, for any kind of
215    overall job and purpose, without being required to communicate about it
216    with the developer or any other specific entity.  In this freedom, it is
217    the <em>user's</em> purpose that matters, not the <em>developer's</em>
218    purpose; you as a user are free to run the program for your purposes,
219    and if you distribute it to someone else, she is then free to run it
220    for her purposes, but you are not entitled to impose your purposes on her.
221    </p>
222    
223    <p>
224    The freedom to run the program as you wish means that you are not
225    forbidden or stopped from making it run.  This has nothing to do with what
226    functionality the program has, whether it is technically capable of
227    functioning in any given environment, or whether it is useful for any
228    particular computing activity.</p>
229    
230    <p>For example, if the code arbitrarily rejects certain meaningful
231    inputs&mdash;or even fails unconditionally&mdash;that may make the
232    program less useful, perhaps even totally useless, but it does not
233    deny users the freedom to run the program, so it does not conflict
234    with freedom 0.  If the program is free, the users can overcome the
235    loss of usefulness, because freedoms 1 and 3 permit users and
236    communities to make and distribute modified versions without the
237    arbitrary nuisance code.</p>
238    
239    <p>&ldquo;As you wish&rdquo; includes, optionally, &ldquo;not at
240    all&rdquo; if that is what you wish.  So there is no need for a
241    separate &ldquo;freedom not to run a program.&rdquo;</p>
242    
243    <h4 id="make-changes">The freedom to study the source code and make changes</h4>
244    
245    <p>
246    In order for freedoms 1 and 3 (the freedom to make changes and the
247    freedom to publish the changed versions) to be meaningful, you need to have
248    access to the source code of the program.  Therefore, accessibility of
249    source code is a necessary condition for free software.  Obfuscated
250    &ldquo;source code&rdquo; is not real source code and does not count
251    as source code.
252    </p>
253    
254    <p>
255    Freedom 1 includes the freedom to use your changed version in place of
256    the original.  If the program is delivered in a product designed to
257    run someone else's modified versions but refuse to run yours&mdash;a
258    practice known as &ldquo;tivoization&rdquo; or &ldquo;lockdown,&rdquo;
259    or (in its practitioners' perverse terminology) as &ldquo;secure
260    boot&rdquo;&mdash;freedom 1 becomes an empty pretense rather than a
261    practical reality.  These binaries are not free
262    software even if the source code they are compiled from is free.
263    </p>
264    
265    <p>
266    One important way to modify a program is by merging in available free
267    subroutines and modules.  If the program's license says that you
268    cannot merge in a suitably licensed existing module&mdash;for instance, if it
269    requires you to be the copyright holder of any code you add&mdash;then the
270    license is too restrictive to qualify as free.
271    </p>
272    
273    <p>
274    Whether a change constitutes an improvement is a subjective matter.
275    If your right to modify a program is limited, in substance, to changes that
276    someone else considers an improvement, that program is not free.
277    </p>
278    
279    <p>
280    One special case of freedom 1 is to delete the program's code so it
281    returns after doing nothing, or make it invoke some other program.
282    Thus, freedom 1 includes the &ldquo;freedom to delete the program.&rdquo;
283    </p>
284    
285    <h4 id="redistribute">The freedom to redistribute if you wish: basic
286    requirements</h4>
287    
288    <p>Freedom to distribute (freedoms 2 and 3) means you are free to
289    redistribute copies, either with or without modifications, either
290    gratis or charging a fee for distribution, to
291    <a href="#exportcontrol">anyone anywhere</a>.  Being free to do these
292    things means (among other things) that you do not have to ask or pay
293    for permission to do so.
294    </p>
295    
296  <P>  <p>
297  You should also have the freedom to make modifications and use them  You should also have the freedom to make modifications and use them
298  privately in your own work or play, without even mentioning that they  privately in your own work or play, without even mentioning that they
299  exist.  If you do publish your changes, you should not be required to  exist.  If you do publish your changes, you should not be required to
300  notify anyone in particular, or in any particular way.  notify anyone in particular, or in any particular way.
301    </p>
302    
303  <P>  <p>
304  The freedom to use a program means the freedom for any kind of person  Freedom 3 includes the freedom to release your modified versions
305  or organization to use it on any kind of computer system, for any kind  as free software.  A free license may also permit other ways of
306  of overall job, and without being required to communicate subsequently  releasing them; in other words, it does not have to be
307  with the developer or any other specific entity.  a <a href="/licenses/copyleft.html">copyleft</a> license.  However, a
308    license that requires modified versions to be nonfree does not qualify
309    as a free license.
310    </p>
311    
312  <P>  <p>
313  The freedom to redistribute copies must include binary or executable  The freedom to redistribute copies must include binary or executable
314  forms of the program, as well as source code, for both modified and  forms of the program, as well as source code, for both modified and
315  unmodified versions.  (Distributing programs in runnable form is  unmodified versions.  (Distributing programs in runnable form is necessary
316  necessary for conveniently installable free operating systems.)  It is  for conveniently installable free operating systems.)  It is OK if there
317  ok if there is no way to produce a binary or executable form for a  is no way to produce a binary or executable form for a certain program
318  certain program (since some languages don't support that feature), but  (since some languages don't support that feature), but you must have the
319  you must have the freedom to redistribute such forms should you find  freedom to redistribute such forms should you find or develop a way to
320  or develop a way to make them.  make them.
321    </p>
322  <P>  
323  In order for the freedoms to make changes, and to publish improved  <h4 id="copyleft">Copyleft</h4>
 versions, to be meaningful, you must have access to the source code of  
 the program.  Therefore, accessibility of source code is a necessary  
 condition for free software.  
   
 <P>  
 In order for these freedoms to be real, they must be irrevocable as  
 long as you do nothing wrong; if the developer of the software has the  
 power to revoke the license, without your doing anything to give  
 cause, the software is not free.  
324    
325  <P>  <p>
326  However, certain kinds of rules about the manner of distributing free  Certain kinds of rules about the manner of distributing free
327  software are acceptable, when they don't conflict with the central  software are acceptable, when they don't conflict with the central
328  freedoms.  For example, copyleft (very simply stated) is the rule that  freedoms.  For example, <a href="/licenses/copyleft.html">copyleft</a>
329  when redistributing the program, you cannot add restrictions to deny  (very simply stated) is the rule that when redistributing the program,
330  other people the central freedoms.  This rule does not conflict with  you cannot add restrictions to deny other people the central freedoms.
331  the central freedoms; rather it protects them.  This rule does not conflict with the central freedoms; rather it
332    protects them.
333  <P>  </p>
334  Thus, you may have paid money to get copies of free software, or you  
335  may have obtained copies at no charge.  But regardless of how you got  <p>
336  your copies, you always have the freedom to copy and change the  In the GNU project, we use copyleft to protect the four freedoms
337  software, even to <A HREF="/philosophy/selling.html">sell copies</A>.  legally for everyone.  We believe there are important reasons why
338  <P>  <a href="/philosophy/pragmatic.html">it is better to use
339    copyleft</a>.  However,
340  ``Free software'' does not mean ``non-commercial''.  A free program  <a href="/philosophy/categories.html#Non-CopyleftedFreeSoftware">
341  must be available for commercial use, commercial development, and  noncopylefted free software</a> is ethical
342  commercial distribution.  Commercial development of free software is  too.  See <a href="/philosophy/categories.html">Categories of Free
343  no longer unusual; such free commercial software is very important.  Software</a> for a description of how &ldquo;free software,&rdquo;
344    &ldquo;copylefted software&rdquo; and other categories of software
345  <P>  relate to each other.
346  Rules about how to package a modified version are acceptable, if they  </p>
347  don't effectively block your freedom to release modified versions.  
348  Rules that ``if you make the program available in this way, you must  <h4 id="packaging">Rules about packaging and distribution details</h4>
349  make it available in that way also'' can be acceptable too, on the  
350  same condition.  (Note that such a rule still leaves you the choice of  <p>
351  whether to publish the program or not.)  It is also acceptable for the  Rules about how to package a modified version are acceptable,
352  license to require that, if you have distributed a modified version  if they don't substantively limit your freedom to release modified
353  and a previous developer asks for a copy of it, you must send one.  versions, or your freedom to make and use modified versions privately.
354    Thus, it is acceptable for the license to require that you change the
355  <P>  name of the modified version, remove a logo, or identify your
356  In the GNU project, we use <A HREF="/copyleft/copyleft.html">  modifications as yours.  As long as these requirements are not so
357  ``copyleft''</A> to protect these freedoms legally for everyone.  But  burdensome that they effectively hamper you from releasing your
358  <A HREF="/philosophy/categories.html#Non-CopyleftedFreeSoftware">  changes, they are acceptable; you're already making other changes to
359  non-copylefted free software</A> also exists.  We believe there are  the program, so you won't have trouble making a few more.
360  important reasons why <A HREF="/philosophy/pragmatic.html"> it is  </p>
361  better to use copyleft</A>, but if your program is non-copylefted free  
362  software, we can still use it.  <p>
363    Rules that &ldquo;if you make your version available in this way, you
364  <P>  must make it available in that way also&rdquo; can be acceptable too,
365  See <A HREF="/philosophy/categories.html">Categories of Free Software  on the same condition.  An example of such an acceptable rule is one
366         (18k characters)</A>  saying that if you have distributed a
367  for a description of how ``free software,'' ``copylefted software'' and  modified version and a previous developer asks for a copy of it, you
368  other categories of software relate to each other.  must send one.  (Note that such a rule still leaves you the choice of
369    whether to distribute your version at all.)  Rules that require release
370  <P>  of source code to the users for versions that you put into public use
371  Sometimes government <A NAME="exportcontrol">export control  are also acceptable.
372  regulations</A> and trade sanctions can constrain your freedom to  </p>
373  distribute copies of programs internationally.  Software developers do  
374  not have the power to eliminate or override these restrictions, but  <p>
375  what they can and must do is refuse to impose them as conditions of  A special issue arises when a license requires changing the name by
376  use of the program.  In this way, the restrictions will not affect  which the program will be invoked from other programs.  That
377  activities and people outside the jurisdictions of these governments.  effectively hampers you from releasing your changed version so that it
378    can replace the original when invoked by those other programs.  This
379  <P>  sort of requirement is acceptable only if there's a suitable aliasing
380  Most free software licenses are based on copyright, and there are  facility that allows you to specify the original program's name as an
381  limits on what kinds of requirements can be imposed through copyright.  alias for the modified version.</p>
382  If a copyright-based license respects freedom in the ways described  
383  above, it is unlikely to have some other sort of problem that we never  <h4 id="exportcontrol">Export regulations</h4>
384  anticipated (though this does happen occasionally).  However, some  
385  free software licenses are based on contracts, and contracts can  <p>
386  impose a much larger range of possible restrictions.  That means there  Sometimes government export control regulations
387  are many possible ways such a license could be unacceptably  and trade sanctions can constrain your freedom to distribute copies of
388  restrictive and non-free.  programs internationally.  Software developers do not have the power to
389  <P>  eliminate or override these restrictions, but what they can and must do
390  We can't possibly list all the possible contract restrictions that  is refuse to impose them as conditions of use of the program.  In this
391  would be unacceptable.  If a contract-based license restricts the user  way, the restrictions will not affect activities and people outside the
392  in an unusual way that copyright-based licenses cannot, and which  jurisdictions of these governments.  Thus, free software licenses
393  isn't mentioned here as legitimate, we will have to think about it,  must not require obedience to any nontrivial export regulations as a
394  and we will probably decide it is non-free.  condition of exercising any of the essential freedoms.
395  <P>  </p>
396  When talking about free software, it is best to avoid using terms like  
397  ``give away'' or ``for free'', because those terms imply that the  <p>
398  issue is about price, not freedom.  Some common terms such as  Merely mentioning the existence of export regulations, without making
399  ``piracy'' embody opinions we hope you won't endorse.  See <A  them a condition of the license itself, is acceptable since it does
400  HREF="/philosophy/words-to-avoid.html">Confusing Words and Phrases  not restrict users.  If an export regulation is actually trivial for
401  that are Worth Avoiding</A> for a discussion of these terms.  free software, then requiring it as a condition is not an actual
402  We also have a list of <A HREF="/philosophy/fs-translations.html">translations  problem; however, it is a potential problem, since a later change in
403  of "free software"</A> into various languages.  export law could make the requirement nontrivial and thus render the
404    software nonfree.
405  <P>  </p>
406    
407  Finally, note that criteria such as those stated in this free software  <h4 id="legal-details">Legal considerations</h4>
408  definition require careful thought for their interpretation.  To  
409  decide whether a specific software license qualifies as a free  <p>
410  software license, we judge it based on these criteria to determine  In order for these freedoms to be real, they must be permanent and
411  whether it fits their spirit as well as the precise words.  If a  irrevocable as long as you do nothing wrong; if the developer of the
412  license includes unconscionable restrictions, we reject it, even if we  software has the power to revoke the license, or retroactively add
413  did not anticipate the issue in these criteria.  Sometimes a license  restrictions to its terms, without your doing anything wrong to give
414  requirement raises an issue that calls for extensive thought,  cause, the software is not free.
415  including discussions with a lawyer, before we can decide if the  </p>
416  requirement is acceptable.  When we reach a conclusion about a new  
417  issue, we often update these criteria to make it easier to see why  <p>
418  certain licenses do or don't qualify.  A free license may not require compliance with the license of a
419    nonfree program.  Thus, for instance, if a license requires you to
420  <P>  comply with the licenses of &ldquo;all the programs you use,&rdquo; in
421    the case of a user that runs nonfree programs this would require
422  If you are interested in whether a specific license qualifies as a  compliance with the licenses of those nonfree programs; that makes the
423  free software license, see our <A  license nonfree.
424  HREF="/licenses/license-list.html">list of licenses</A>.  If the  </p>
425  license you are concerned with is not listed there, you can ask us  
426  about it by sending us email at <A  <p>
427  HREF="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</A>.  It is acceptable for a free license to specify which jurisdiction's
428    law applies, or where litigation must be done, or both.
429  <HR>  </p>
430    
431  <H4><A HREF="/philosophy/philosophy.html">Other Texts to Read</A></H4>  <h4 id="contracts">Contract-based licenses</h4>
432    
433  <P>  <p>
434  Another group has started using the term "open source" to mean  Most free software licenses are based on copyright, and there are limits
435  something close (but not identical) to "free software".  We prefer the  on what kinds of requirements can be imposed through copyright.  If a
436  term "free software" because, once you have heard it refers to freedom  copyright-based license respects freedom in the ways described above, it
437  rather than price, <A HREF="free-software-for-freedom.html">it calls  is unlikely to have some other sort of problem that we never anticipated
438  to mind freedom</A>.  (though this does happen occasionally).  However, some free software
439    licenses are based on contracts, and contracts can impose a much larger
440  <HR>  range of possible restrictions.  That means there are many possible ways
441  [  such a license could be unacceptably restrictive and nonfree.
442  <!-- Please keep this list alphabetical -->  </p>
443  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  
444  <A HREF="/philosophy/free-sw.hr.html">Croatian</A>  <p>
445  | <A HREF="/philosophy/free-sw.cs.html">Czech</A>  We can't possibly list all the ways that might happen.  If a
446  | <A HREF="/philosophy/free-sw.da.html">Danish</A>  contract-based license restricts the user in an unusual way that
447  | <A HREF="/philosophy/free-sw.nl.html">Dutch</A>  copyright-based licenses cannot, and which isn't mentioned here as
448  | <A HREF="/philosophy/free-sw.html">English</A>  legitimate, we will have to think about it, and we will probably conclude
449  | <A HREF="/philosophy/free-sw.fr.html">French</A>  it is nonfree.
450  | <A HREF="/philosophy/free-sw.gl.html">Galician</A>  </p>
451  | <A HREF="/philosophy/free-sw.de.html">German</A>  
452  | <A HREF="/philosophy/free-sw.hu.html">Hungarian</A>  <h3 id="in-practice">The Free Software Definition in Practice</h3>
453  | <A HREF="/philosophy/free-sw.id.html">Indonesian</A>  
454  | <A HREF="/philosophy/free-sw.it.html">Italian</A>  <h4 id="interpretation">How we interpret these criteria</h4>
455  | <A HREF="/philosophy/free-sw.ja.html">Japanese</A>  
456  | <A HREF="/philosophy/free-sw.ko.html">Korean</A>  <p>
457  | <A HREF="/philosophy/free-sw.no.html">Norwegian</A>  Note that criteria such as those stated in this free software
458  | <A HREF="/philosophy/free-sw.pl.html">Polish</A>  definition require careful thought for their interpretation.  To decide
459  | <A HREF="/philosophy/free-sw.pt.html">Portuguese</A>  whether a specific software license qualifies as a free software license,
460  | <A HREF="/philosophy/free-sw.ro.html">Romanian</A>  we judge it based on these criteria to determine whether it fits their
461  | <A HREF="/philosophy/free-sw.ru.html">Russian</A>  spirit as well as the precise words.  If a license includes unconscionable
462  | <A HREF="/philosophy/free-sw.sl.html">Slovenian</A>        restrictions, we reject it, even if we did not anticipate the issue
463  | <A HREF="/philosophy/free-sw.es.html">Spanish</A>  in these criteria.  Sometimes a license requirement raises an issue
464  | <A HREF="/philosophy/free-sw.tr.html">Turkish</A>  that calls for extensive thought, including discussions with a lawyer,
465  <!-- Please keep this list alphabetical -->  before we can decide if the requirement is acceptable.  When we reach
466  <!-- PLEASE UPDATE THE LIST AT THE BOTTOM (OR TOP) OF THE PAGE TOO! -->  a conclusion about a new issue, we often update these criteria to make
467  ]  it easier to see why certain licenses do or don't qualify.
468  <P>  </p>
469  Return to <A HREF="/home.html">GNU's home page</A>.  
470  <P>  <h4 id="get-help">Get help with free licenses</h4>
471    
472  Please send FSF &amp; GNU inquiries &amp; questions to  <p>
473    If you are interested in whether a specific license qualifies as a free
474  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  software license, see our <a href="/licenses/license-list.html">list
475  There are also <A HREF="/home.html#ContactInfo">other ways to  of licenses</a>.  If the license you are concerned with is not
476  contact</A> the FSF.  listed there, you can ask us about it by sending us email at
477  <P>  <a href="mailto:licensing@gnu.org">&lt;licensing@gnu.org&gt;</a>.
478    </p>
479  Please send comments on these web pages to  
480    <p>
481  <A HREF="mailto:webmasters@gnu.org"><EM>webmasters@gnu.org</EM></A>,  If you are contemplating writing a new license, please contact the
482  send other questions to  Free Software Foundation first by writing to that address. The
483  <A HREF="mailto:gnu@gnu.org"><EM>gnu@gnu.org</EM></A>.  proliferation of different free software licenses means increased work
484  <P>  for users in understanding the licenses; we may be able to help you
485  Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, Free  find an existing free software license that meets your needs.
486  Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  </p>
487  02111,  USA  
488  <P>  <p>
489  Verbatim copying and distribution of this entire article is  If that isn't possible, if you really need a new license, with our
490  permitted in any medium, provided this notice is preserved.  help you can ensure that the license really is a free software license
491  <P>  and avoid various practical problems.
492  Updated:  </p>
493    
494    <h4 id="terminology">Use the right words when talking about free software</h4>
495    
496    <p>
497    When talking about free software, it is best to avoid using terms
498    like &ldquo;give away&rdquo; or &ldquo;for free,&rdquo; because those terms imply that
499    the issue is about price, not freedom.  Some common terms such
500    as &ldquo;piracy&rdquo; embody opinions we hope you won't endorse.  See
501    <a href="/philosophy/words-to-avoid.html">Confusing Words and Phrases that
502    are Worth Avoiding</a> for a discussion of these terms.  We also have
503    a list of proper <a href="/philosophy/fs-translations.html">translations of
504    &ldquo;free software&rdquo;</a> into various languages.
505    </p>
506    
507    <p id="open-source">
508    Another group uses the term &ldquo;open source&rdquo; to mean
509    something close (but not identical) to &ldquo;free software.&rdquo;  We
510    prefer the term &ldquo;free software&rdquo; because, once you have heard that
511    it refers to freedom rather than price, it calls to mind freedom.  The
512    word &ldquo;open&rdquo; never refers to freedom.
513    </p>
514    
515    <h3 id="beyond-software">Beyond Software</h3>
516    
517    <p>
518    <a href="/philosophy/free-doc.html">Software manuals must be free</a>,
519    for the same reasons that software must be free, and because the
520    manuals are in effect part of the software.
521    </p>
522    
523    <p>
524    The same arguments also make sense for other kinds of works of
525    practical use&mdash;that is to say, works that embody useful knowledge,
526    such as educational works and reference
527    works.  <a href="https://wikipedia.org">Wikipedia</a> is the best-known
528    example.
529    </p>
530    
531    <p>
532    Any kind of work <em>can</em> be free, and the definition of free software
533    has been extended to a definition of <a href="http://freedomdefined.org/">
534    free cultural works</a> applicable to any kind of works.
535    </p>
536    
537    <h3 id="History">History</h3>
538    
539    <p>From time to time we revise this Free Software Definition.  Here is
540    the list of substantive changes, along with links to show exactly what
541    was changed.</p>
542    
543    <ul>
544    
545    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.168&amp;r2=1.169">Version
546    1.169</a>: Explain more clearly why the four freedoms must apply
547    to commercial activity.  Explain why the four freedoms imply the
548    freedom not to run the program and the freedom to delete it, so there
549    is no need to state those as separate requirements.</li>
550    
551    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.164&amp;r2=1.165">Version
552    1.165</a>: Clarify that arbitrary annoyances in the code do not
553    negate freedom 0, and that freedoms 1 and 3 enable users to remove them.</li>
554    
555    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.152&amp;r2=1.153">Version
556    1.153</a>: Clarify that freedom to run the program means nothing stops
557    you from making it run.</li>
558    
559    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.140&amp;r2=1.141">Version
560    1.141</a>: Clarify which code needs to be free.</li>
561    
562    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.134&amp;r2=1.135">Version
563    1.135</a>: Say each time that freedom 0 is the freedom to run the program
564    as you wish.</li>
565    
566    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.133&amp;r2=1.134">Version
567    1.134</a>: Freedom 0 is not a matter of the program's functionality.</li>
568    
569    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.130&amp;r2=1.131">Version
570    1.131</a>: A free license may not require compliance with a nonfree license
571    of another program.</li>
572    
573    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.128&amp;r2=1.129">Version
574    1.129</a>: State explicitly that choice of law and choice of forum
575    specifications are allowed.  (This was always our policy.)</li>
576    
577    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.121&amp;r2=1.122">Version
578    1.122</a>: An export control requirement is a real problem if the
579    requirement is nontrivial; otherwise it is only a potential problem.</li>
580    
581    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.117&amp;r2=1.118">Version
582    1.118</a>: Clarification: the issue is limits on your right to modify,
583    not on what modifications you have made.  And modifications are not limited
584    to &ldquo;improvements&rdquo;</li>
585    
586    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.110&amp;r2=1.111">Version
587    1.111</a>: Clarify 1.77 by saying that only
588    retroactive <em>restrictions</em> are unacceptable.  The copyright
589    holders can always grant additional <em>permission</em> for use of the
590    work by releasing the work in another way in parallel.</li>
591    
592    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.104&amp;r2=1.105">Version
593    1.105</a>: Reflect, in the brief statement of freedom 1, the point
594    (already stated in version 1.80) that it includes really using your modified
595    version for your computing.</li>
596    
597    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.91&amp;r2=1.92">Version
598    1.92</a>: Clarify that obfuscated code does not qualify as source code.</li>
599    
600    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.89&amp;r2=1.90">Version
601    1.90</a>: Clarify that freedom 3 means the right to distribute copies
602    of your own modified or improved version, not a right to participate
603    in someone else's development project.</li>
604    
605    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.88&amp;r2=1.89">Version
606    1.89</a>: Freedom 3 includes the right to release modified versions as
607    free software.</li>
608    
609    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.79&amp;r2=1.80">Version
610    1.80</a>: Freedom 1 must be practical, not just theoretical;
611    i.e., no tivoization.</li>
612    
613    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.76&amp;r2=1.77">Version
614    1.77</a>: Clarify that all retroactive changes to the license are
615    unacceptable, even if it's not described as a complete
616    replacement.</li>
617    
618    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.73&amp;r2=1.74">Version
619    1.74</a>: Four clarifications of points not explicit enough, or stated
620    in some places but not reflected everywhere:
621    <ul>
622    <li>&ldquo;Improvements&rdquo; does not mean the license can
623    substantively limit what kinds of modified versions you can release.
624    Freedom 3 includes distributing modified versions, not just changes.</li>
625    <li>The right to merge in existing modules
626    refers to those that are suitably licensed.</li>
627    <li>Explicitly state the conclusion of the point about export controls.</li>
628    <li>Imposing a license change constitutes revoking the old license.</li>
629    </ul>
630    </li>
631    
632    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.56&amp;r2=1.57">Version
633    1.57</a>: Add &ldquo;Beyond Software&rdquo; section.</li>
634    
635    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.45&amp;r2=1.46">Version
636    1.46</a>: Clarify whose purpose is significant in the freedom to run
637    the program for any purpose.</li>
638    
639    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.40&amp;r2=1.41">Version
640    1.41</a>: Clarify wording about contract-based licenses.</li>
641    
642    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.39&amp;r2=1.40">Version
643    1.40</a>: Explain that a free license must allow to you use other
644    available free software to create your modifications.</li>
645    
646    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.38&amp;r2=1.39">Version
647    1.39</a>: Note that it is acceptable for a license to require you to
648    provide source for versions of the software you put into public
649    use.</li>
650    
651    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.30&amp;r2=1.31">Version
652    1.31</a>: Note that it is acceptable for a license to require you to
653    identify yourself as the author of modifications.  Other minor
654    clarifications throughout the text.</li>
655    
656    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.22&amp;r2=1.23">Version
657    1.23</a>: Address potential problems related to contract-based
658    licenses.</li>
659    
660    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.15&amp;r2=1.16">Version
661    1.16</a>: Explain why distribution of binaries is important.</li>
662    
663    <li><a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;r1=1.10&amp;r2=1.11">Version
664    1.11</a>: Note that a free license may require you to send a copy of
665    versions you distribute to previous developers on request.</li>
666    
667    </ul>
668    
669    <p>There are gaps in the version numbers shown above because there are
670    other changes in this page that do not affect the definition or its
671    interpretations.  For instance, the list does not include changes in
672    asides, formatting, spelling, punctuation, or other parts of the page.
673    You can review the complete list of changes to the page through
674    the <a href="//web.cvs.savannah.gnu.org/viewvc/www/philosophy/free-sw.html?root=www&amp;view=log">cvsweb
675    interface</a>.</p>
676    <div class="column-limit"></div>
677    
678    <h3 class="footnote">Footnote</h3>
679    <ol>
680    <li id="f1">The reason they are numbered 0, 1, 2 and 3 is historical. Around
681    1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that
682    the freedom to run the program needed to be mentioned explicitly.
683    It was clearly more basic than the other three, so it properly should
684    precede them. Rather than renumber the others, we made it freedom&nbsp;0.</li>
685    </ol>
686    </div>
687    
688    </div><!-- for id="content", starts in the include above -->
689    <!--#include virtual="/server/footer.html" -->
690    <div id="footer" role="contentinfo">
691    <div class="unprintable">
692    
693    <p>Please send general FSF &amp; GNU inquiries to
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699    <p><!-- TRANSLATORS: Ignore the original text in this paragraph,
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