How does ShareAlike work?
ShareAlike means that if you share an adaptation of a CC BY-SA work, you must license the adaptation under the same Creative Commons license or an officially compatible one. The condition triggers only when you share Adapted Material. It does not trigger when the unchanged work appears in a collection with other separate works. The decisive exception: an ND license on the original work blocks sharing the adaptation entirely. Your first move is to decide whether your use is an adaptation or a collection. Then test ND, SA, and adapter-license consequences.
When ShareAlike Attaches
ShareAlike does not attach to using an unchanged work. Copy a CC BY-SA photo onto a blog, into a presentation, or onto social media. You do not trigger SA. The condition activates only when you create and share Adapted Material.
What Counts as Adapted Material
Adapted Material is a work based on the original that requires copyright permission to create. Under the 4.0 license definitions, translation is normally an adaptation. Synchronising music with a moving image is expressly Adapted Material. Converting a PDF to plain text is not. Format conversion alone does not create Adapted Material.
The Sharing Trigger
The distinction is sharing. Build an adaptation for private use under any CC license, including ND, without triggering SA. Distribute that adaptation to the public, and SA applies if the original license included the SA condition.
What ShareAlike Does Not Extend To
ShareAlike does not apply to collections. A collection keeps separate works separate: an anthology of essays, a compilation of photos on a single webpage. Each work keeps its own license. The collection's overall license does not replace those individual terms. Combine a CC BY-SA essay with a CC BY-NC essay in a collection. The BY-SA essay stays under BY-SA.
ShareAlike does not extend to the original work itself. The original creator's license never changes. Only your contribution, the new copyrightable material you added, must carry the SA license. You must still retain the original attribution and license notice for the source work.
ShareAlike does not create compatibility between two different SA licenses. Trust the official compatibility list. Creative Commons lists one-way compatibility from CC BY-SA 4.0 to GPLv3 for adapted material. This does not turn a CC instrument into a software license. It does not create compatibility in the reverse direction.
| Question | If Yes | If No |
|---|---|---|
| Is your planned use sharing Adapted Material? | SA applies. You must license your adaptation under the same SA license or a compatible one. | SA does not apply. Proceed under the original license's terms. |
| Does the original work carry a NoDerivatives condition? | You cannot share Adapted Material at all. You may create adaptations for private use only. | You can create and share adaptations, but check SA and NC conditions. |
| Does the original work carry a ShareAlike condition? | Your adaptation must use the same SA license or an officially compatible license. | No adapter-license restriction. Use any CC license for your adaptation. |
| Are you combining multiple CC-licensed works in a single adaptation? | Test each input for SA. If any input is SA, your entire adaptation must carry that SA license or a compatible license. | No SA trigger from the inputs. Combine freely but respect other conditions. |
| Is the intended use purely a collection with no modifications? | SA does not apply. Each work keeps its own license. | If you are modifying works, the collection analysis does not apply. Test as adaptation. |
Testing ND, SA, And Adapter-Licence Consequences
Before you reuse any CC-licensed work, run three tests in order.
First Test: NoDerivatives
Check whether the original license includes NoDerivatives. If ND is present, you may not share an adaptation. Period. Share the unmodified work itself, including for commercial use. You cannot translate or synchronise it with music in a way that creates an adaptation under copyright law. Cropping, excerpting, and combining may or may not create an adaptation. That depends on applicable copyright law. Translation and music synchronisation are the categorical examples.
Second Test: ShareAlike
Check whether the original license includes ShareAlike. If SA is present, your adaptation must carry the same Creative Commons license or an officially compatible one. Consult the official compatibility list. Do not assume two SA licenses are compatible. Check the list published by Creative Commons.
Third Test: Your Adapter License
Determine what license you must apply to your adaptation. Use the same SA license version as the original. If the original uses CC BY-SA 4.0, your adaptation must use CC BY-SA 4.0. You may also use a license that Creative Commons has formally named as compatible. The only current example is GPLv3 for adapted material, and that compatibility is one-way only.
What Happens When You Get It Wrong
Share an adaptation without applying the required SA license and you have breached the terms. Under the 4.0 licenses, rights terminate automatically on breach. They are automatically reinstated from the date you cure the violation if you cure it within 30 days after you become aware of the breach. Cure does not erase possible liability for the period of violation. Older license versions have different termination language. They do not contain the automatic 30-day cure mechanism.
Combining multiple CC-licensed works in a single adaptation? Test each input for SA. If any input is SA, your entire adaptation must carry that SA license or a compatible one. This can create practical incompatibilities. Combine a CC BY-SA photo with a CC BY-NC-SA photo and your adaptation must satisfy both SA conditions. NC and SA together require a BY-NC-SA license, a separate official instrument in the suite.
Common Questions
Does ShareAlike apply to collections?
No. ShareAlike does not apply to collections. A collection keeps separate works separate: an anthology of essays, a compilation of photos. Each work keeps its own license. The collection's overall license does not replace those individual terms. Only when you create Adapted Material, modifying the work in a way that requires copyright permission, does SA trigger.
Can I use a CC BY-SA work in a commercial project?
Yes. CC BY-SA permits commercial use. The SA condition only requires that if you share an adaptation, you must license it under the same SA license or a compatible one. Use the original work itself commercially without restriction: advertising, product packaging, for-profit publications.
What licence do I apply to my adaptation of a CC BY-SA work?
Apply the same SA license version as the original. For a CC BY-SA 4.0 work, your adaptation must use CC BY-SA 4.0. You may also use a license that Creative Commons has formally named as compatible. The only current example is GPLv3 for adapted material, and this compatibility is one-way only.
If I crop a CC BY-SA photo, is that an adaptation that triggers SA?
Whether cropping creates an adaptation depends on applicable copyright law. The 4.0 definitions do not give a universal answer. If cropping is not a copyright-relevant modification under your jurisdiction's law, it is not Adapted Material, and SA does not apply. If it is an adaptation, SA would apply when you share the cropped version.
Can I translate a CC BY-SA work without triggering SA?
Translation is normally an adaptation under the 4.0 definition. Translate a CC BY-SA work and share the translation, and you must license the translation under the same SA license or a compatible one. If the original work uses ND, you cannot share the translation at all.
What happens if I share an adaptation without the required SA licence?
You have breached the license. Under 4.0, rights terminate automatically on breach. They are automatically reinstated from the date you cure the violation if you cure it within 30 days after you become aware of the breach. Cure does not erase possible liability for the period of violation. Older license versions have different termination rules.
Can the original creator change the licence after I have used the work?
No. The licensor may stop distributing the work or offer it under other terms, but cannot withdraw the license from people who already received it while complying with its terms. This is a fundamental feature of Creative Commons instruments. The license is irrevocable for the material you already obtained under the terms in effect at the time.