MIT vs LGPL-3.0 License

MIT License compared with GNU Lesser General Public License v3.0: what each licence allows, and whether code under one can be used in a project under the other. Results are generated by the open-source license compatibility checker.

Quick Answer

Compatibility is directional, so both directions are answered separately (distributed software):

MIT code in a project licensed under LGPL-3.0

Generally Compatible

Using MIT-licensed code in a project under LGPL-3.0 is generally compatible in this scenario.

MIT permits commercial use.

LGPL-3.0 code in a project licensed under MIT

Compatible With Conditions

Using LGPL-3.0-licensed code in a project under MIT is generally possible if the listed conditions are met.

An application that uses an LGPL-3.0 library may be distributed under its own terms, including proprietary terms, when section 4 is met: typically by using the library as a replaceable shared library, giving notice of its use, and including the licence.

Key Differences

Copyleft: MIT: none; LGPL-3.0: weak (library / module level).
Source disclosure: MIT: not required; LGPL-3.0: the library and changes to it.
Same licence for distributed changes: MIT: no; LGPL-3.0: yes.
Mark modified files: MIT: no; LGPL-3.0: yes.
Express patent licence: MIT: no; LGPL-3.0: yes.
Patent termination clause: MIT: no; LGPL-3.0: yes.

Comparison Table

	MIT	LGPL-3.0
Type	Open source	Open source
OSI approved	Yes	Yes
Commercial use	Permitted	Permitted
Modification	Permitted	Permitted
Distribution	Permitted	Permitted
Copyleft	None	Weak (library / module level)
Network-use (SaaS) clause	No	No
Source disclosure	Not required	The library and changes to it
Same licence for distributed changes	No	Yes
Attribution / notices	Yes	Yes
Mark modified files	No	Yes
Express patent licence	No	Yes
Patent termination clause	No	Yes
Trademark rights granted	Not addressed	Not addressed

Commercial Use

MIT: permitted.
LGPL-3.0: permitted.

MIT code in a project licensed under LGPL-3.0: MIT permits commercial use.
LGPL-3.0 code in a project licensed under MIT: LGPL-3.0 permits commercial use. Commercial use, including selling copies, is allowed; the copyleft conditions still apply to how the code is distributed.

Proprietary Software

MIT code in closed-source commercial software

Generally Compatible

Using MIT-licensed code in a proprietary project is generally compatible in this scenario.

MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

LGPL-3.0 code in closed-source commercial software

Compatible With Conditions

Using LGPL-3.0-licensed code in a proprietary project is generally possible if the listed conditions are met.

MIT code in closed-source commercial software: MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.
LGPL-3.0 code in closed-source commercial software: An application that uses an LGPL-3.0 library may be distributed under its own terms, including proprietary terms, when section 4 is met: typically by using the library as a replaceable shared library, giving notice of its use, and including the licence.

SaaS

Network-use clause: MIT: no; LGPL-3.0: no.

MIT code in a closed-source SaaS

Generally Compatible

Using MIT-licensed code in a proprietary project is generally compatible in this scenario.

MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

LGPL-3.0 code in a closed-source SaaS

Generally Compatible

Using LGPL-3.0-licensed code in a proprietary project is generally compatible in this scenario.

LGPL-3.0 copyleft conditions are triggered by distribution; this scenario does not include distribution.

MIT code in a closed-source SaaS: MIT has no network-use (SaaS) clause.
LGPL-3.0 code in a closed-source SaaS: LGPL-3.0 has no network-use (SaaS) clause.

Modification

MIT: permitted.
LGPL-3.0: permitted; modified files must be marked.

Modifying MIT code used in closed-source software

Generally Compatible

Using MIT-licensed code in a proprietary project is generally compatible in this scenario.

MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

Modifying LGPL-3.0 code used in closed-source software

Compatible With Conditions

Using LGPL-3.0-licensed code in a proprietary project is generally possible if the listed conditions are met.

Modifying MIT code used in closed-source software: MIT permits modification.
Modifying LGPL-3.0 code used in closed-source software: LGPL-3.0 permits modification. LGPL-3.0 requires modified files to carry notices stating that they were changed.

Distribution

MIT: permitted.
LGPL-3.0: permitted.

MIT code in a project licensed under LGPL-3.0: MIT permits distribution.
LGPL-3.0 code in a project licensed under MIT: LGPL-3.0 permits distribution subject to its copyleft conditions.

Copyleft

MIT: none copyleft.
LGPL-3.0: weak (library / module level) copyleft.

MIT code in a project licensed under LGPL-3.0: MIT has no copyleft.
LGPL-3.0 code in a project licensed under MIT: An application that uses an LGPL-3.0 library may be distributed under its own terms, including proprietary terms, when section 4 is met: typically by using the library as a replaceable shared library, giving notice of its use, and including the licence.

Source Disclosure

MIT: not required.
LGPL-3.0: the library and changes to it.

MIT code in a project licensed under LGPL-3.0: MIT does not require you to publish source code.
LGPL-3.0 code in a project licensed under MIT: An application that uses an LGPL-3.0 library may be distributed under its own terms, including proprietary terms, when section 4 is met: typically by using the library as a replaceable shared library, giving notice of its use, and including the licence.

Attribution

MIT: Include the copyright notice and permission notice in all copies or substantial portions.
LGPL-3.0: Provide source of the library and of modifications to it when distributing.
LGPL-3.0: Give prominent notice that the library is used and that it is covered by the LGPL.
LGPL-3.0: Accompany the Combined Work with copies of the GPL and LGPL.
LGPL-3.0: Provide a way to relink or use a shared library so users can run a modified library version (section 4(d)).
LGPL-3.0: Provide Installation Information where required for User Products.

MIT code in a project licensed under LGPL-3.0: MIT requires the copyright and licence notices to be kept with copies you distribute.
LGPL-3.0 code in a project licensed under MIT: LGPL-3.0 requires the copyright and licence notices to be kept with copies you distribute.

Patent Considerations

Express patent licence: MIT: no; LGPL-3.0: yes.
Patent termination clause: MIT: no; LGPL-3.0: yes.

MIT code in a project licensed under LGPL-3.0: MIT contains no express patent licence. Any patent permission would depend on implied licence doctrines, which vary by jurisdiction.
LGPL-3.0 code in a project licensed under MIT: LGPL-3.0 includes an express patent licence from contributors. That patent licence terminates for anyone who initiates patent litigation alleging that the work infringes a patent.

Common Scenarios

Scenario	MIT code in a project licensed under LGPL-3.0	LGPL-3.0 code in a project licensed under MIT
Use as a dependency / library	Generally Compatible	Compatible With Conditions
Copy source code into the project	Generally Compatible	Potential Conflict
Modify the component	Generally Compatible	Compatible With Conditions
SaaS / network service (not distributed)	Generally Compatible	Generally Compatible
Internal / private use only	Generally Compatible	Generally Compatible
Resell the software	Generally Compatible	Compatible With Conditions
White-label / rebrand	Generally Compatible	Compatible With Conditions

FAQ

Can I use MIT code in a project licensed under LGPL-3.0?

Using MIT-licensed code in a project under LGPL-3.0 is generally compatible in this scenario. MIT permits commercial use.

Can I use LGPL-3.0 code in a project licensed under MIT?

Using LGPL-3.0-licensed code in a project under MIT is generally possible if the listed conditions are met. An application that uses an LGPL-3.0 library may be distributed under its own terms, including proprietary terms, when section 4 is met: typically by using the library as a replaceable shared library, giving notice of its use, and including the licence.

Can MIT-licensed code be used in closed-source commercial software?

Using MIT-licensed code in a proprietary project is generally compatible in this scenario. MIT generally allows the code to be included in proprietary software without releasing your source code, provided its notices are kept.

Can LGPL-3.0-licensed code be used in closed-source commercial software?

Using LGPL-3.0-licensed code in a proprietary project is generally possible if the listed conditions are met. An application that uses an LGPL-3.0 library may be distributed under its own terms, including proprietary terms, when section 4 is met: typically by using the library as a replaceable shared library, giving notice of its use, and including the licence.

Do I have to publish my source code when I use MIT code?

MIT does not require you to publish source code.

Do I have to publish my source code when I use LGPL-3.0 code?

Can I use MIT code in a closed-source SaaS?

Can I use LGPL-3.0 code in a closed-source SaaS?

Using LGPL-3.0-licensed code in a proprietary project is generally compatible in this scenario. LGPL-3.0 copyleft conditions are triggered by distribution; this scenario does not include distribution.

Try the Interactive Checker

Change the scenario, say whether the code is modified, distributed or offered as SaaS, and see every rule that applies.

Check MIT in a LGPL-3.0 project Check LGPL-3.0 in a MIT project

Related Comparisons

Authoritative Sources

This tool provides general software licensing information and is not legal advice. License obligations may depend on how software components are combined, modified, distributed and used. For high-risk results, review the actual license text before relying on this result.