I'm taking the following Stack Overflow question and its answers into consideration: Can you create your one software license?

My question here however is not creating a completely new license from scratch (as I am not a lawyer and wouldn't know where to start), but rather slightly modifying an existing one and saving it under a new name.

Is this possible? Are licenses licensed themselves?

Does a new 'custom' license need to be approved by official organizations?

  • Which license would you like to start from?
    – user114
    Commented Jun 24, 2015 at 8:31
  • It makes only sense in a low number of cases to build up your own licence. There are a huge number already and many of them allow it to attribute it.
    – frlan
    Commented Jun 24, 2015 at 8:33
  • 1
    Yes you can but why would you and its likely to cause you trouble. Anyone can create a licence for anything, doesnt mean it will stand up in court.
    – Toby Allen
    Commented Jun 24, 2015 at 11:34
  • 1
    Related (not dupe): opensource.stackexchange.com/q/253/235.
    – TRiG
    Commented Jun 24, 2015 at 12:31

4 Answers 4


Licenses themselves are often licensed under separate terms which don't have much to do with their own. The GPLv3, for example is licensed under the following terms:

Copyright © 2007 Free Software Foundation, Inc. http://fsf.org/

Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

Which is definitely not a free-as-in-freedom license. You need to check for each license separately which conditions apply to the license text itself. In the worst case the license text is not licensed at all, which implies All Rights Reserved which means you are not allowed to use it for your own project, because that would be an illegal reproduction of the copyrighted license text.

But even when the license of the license allows modification: Unless you are a lawyer specialized in copyright law you should not modify an existing license. A license is a legal document, and writing legal documents should be left to the professionals. Otherwise you risk writing something which doesn't actually say what you want it to say.

Another reason to not invent your own license is to prevent license proliferation. There are already lots and lots of open source licenses with very similar terms, but yet they are often incompatible just because they say so. Inventing a new license even though an existing one would do makes it harder for all of us to keep track of all the licenses available and is a hinderance to developers who would like to combine code licensed under different licenses in one project. So unless you are sure your new license fills an important niche not yet covered, please try to use one which already exists.

Regarding "approval for new licenses": A license is a legal agreement between you and your users. Nobody needs to approve it except for you and your users for it to be legally valid (except when it contradicts local laws - that's another reason why you should let a lawyer write them). However, when you want others to use your license for their FOSS project, you might seek approval from a quasi-official organization like the Free Software Foundation or Open Source Initiative. Their recommendation might not have any legal weight, but it confirms that your terms are in agreement with their definitions of Free Software / Open Source Software.


The main problem you may find if you change an existing license is enforcement. The mainstream licenses have been carefully drafted with enforceability in mind - and some courts have now ruled on those licenses.

If you modify an existing license with your own wording, you may introduce some language that makes your license unenforceable - even if your new wording is fine, you won't be able to fully benefit from previous rulings and increase your risk of a ruling going against you.

But what you suggest has been done in the past. For example Bloomberg have open sourced a proprietary API under a “free-use” MIT-style license (differences emphasised). These changes have certainly gone through the hands of a number of legal experts before being applied.

Permission is hereby granted, free of charge, to any person obtaining a copy of this proprietary software and associated documentation files (the "Software"), to use, publish, or distribute copies of the Software, and to permit persons to whom the Software is furnished to do so.

Any other use, including modifying, adapting, reverse engineering, decompiling, or disassembling, is not permitted.

[... - rest is the same]

Original License:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

[... - rest is the same]


Yes, as long as you check.

Some licenses allow you to do this. Notably, the GPL does, though the note indicates otherwise: see this answer for a full explanation.

It should simply be a matter of checking around the license creator's website or distribution mechanism to see whether they'd allow you to use their license to create a new one.

If there is nothing saying you can (explicitly giving you permission), you may not. It is a common misconception that if no license terms are available, you can do anything you like with it: this is not true. Instead, if no licenses is visible, you can do almost nothing with it (excepting fair use). So, if they don't give permission, you can't use the license.

You should also note that creating your own license is discouraged by many, notably GNU (creators of the GPL). They say that although you may use the GPL to create a new license, the new license will almost certainly be incompatible with the GPL. This reason sticks as a good reason not to write your own license based off any other. Additionally, the big-name accepted licenses like Apache, MIT, and GPL are legally vetted for you and you can be sure that there aren't (m)any holes. Your own license, unless you are a lawyer, likely will.


Can I create my own license by modifying an existing one? Is that possible?

Basically, yes. It was done in the past. You should give it a different name though, to avoid confusion.

Are licenses licensed themselves?

I don't know of any examples where that is the case.

Does a new 'custom' license need to be approved by official organs?

No, you can put your works under any license you seem fit. Approval isn't required. A recommendation by the OSI or the FSF might be helpful to popularize your license though. Also the checkup with the two organizations might reveal some problem with your license.

  • 3
    Well, actually of course do licences have a copyright and therefore it depends on the author whether you can fork it. Most of them are fine with it as long as you don't keep it calling the old name. But some of them are quiet pissy about.
    – frlan
    Commented Jun 24, 2015 at 8:32
  • @frlan: Do you have examples of licenses that got a license themself and the author of the license being pissy about forking? I don't know any, but if you can provide examples that would be good to put in an answer of your own. Such information might be helpful.
    – Mnementh
    Commented Jun 24, 2015 at 8:35
  • 1
    I'd like to add to this that having your license approved by an official instance will make people less hesitant to use your license since it is less likely to contain any dangerous loopholes.
    – overactor
    Commented Jun 24, 2015 at 8:39
  • 2
    The GPLv3, for example, is "Copyright © 2007 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.".
    – Philipp
    Commented Jun 24, 2015 at 11:17
  • @Philipp: Interesting. I think it is more directed at people creating a different GPL to change terms but still calling it GPL. As long as you rename it I doubt the FSF will come after you.
    – Mnementh
    Commented Jun 24, 2015 at 11:29

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