Always copy the license text from the official source below, not from a third-party page, and keep the version number. Our guide to choosing an open hardware license explains the differences in more depth, and the chooser narrows the list for your project.
| License | SPDX identifier | Family |
|---|---|---|
| CERN-OHL-S v2 | CERN-OHL-S-2.0 |
Strongly reciprocal |
| CERN-OHL-W v2 | CERN-OHL-W-2.0 |
Weakly reciprocal |
| CERN-OHL-P v2 | CERN-OHL-P-2.0 |
Permissive |
| Solderpad Hardware License 2.1 | SHL-2.1 |
Permissive |
| TAPR Open Hardware License 1.0 | TAPR-OHL-1.0 |
Reciprocal |
| CC BY-SA 4.0 | CC-BY-SA-4.0 |
Share-alike (documentation) |
| CC BY 4.0 | CC-BY-4.0 |
Attribution (documentation) |
CERN-OHL-S v2
The strongly reciprocal variant of the CERN Open Hardware Licence, published by CERN in 2020. Anyone who distributes a product or a modified design must make the complete source available under the same license, apart from standard "available components." Includes an express patent license. Approved by the Open Source Initiative.
Use it when you want every derivative of your design to stay open.
Official text: cern_ohl_s_v2.txt (also as PDF). CERN's license home page links to all variants and the rationale document.
CERN-OHL-W v2
The weakly reciprocal variant. Changes to the licensed design must be shared under the same license, but the design can be combined with other, closed designs without opening them. Includes an express patent license. OSI approved.
Use it for modules, IP cores and building blocks that other people will put into larger products.
Official text: cern_ohl_w_v2.txt (also as PDF).
CERN-OHL-P v2
The permissive variant. Anyone may use, modify, make and sell products from the design under any terms, provided notices are kept with the source and products. Includes an express patent license and hardware-specific definitions. OSI approved.
Use it when you want the widest possible reuse, including in closed products.
Official text: cern_ohl_p_v2.txt (also as PDF).
Solderpad Hardware License 2.1
A permissive license that wraps the Apache License 2.0 and extends it to hardware and design rights. Inherits Apache's patent grant and its patent-termination clause. Maintained by the FOSSi Foundation since 2020.
Use it for chip designs, HDL and processor cores, where Apache 2.0 is already familiar to the companies involved.
Official text: SHL-2.1 on solderpad.org.
TAPR Open Hardware License 1.0
Published in 2007 by TAPR, a nonprofit amateur radio organization, and one of the first hardware-specific licenses. Reciprocal: modified documentation must stay under the TAPR OHL and be emailed to earlier licensors who gave an address. Includes a promise not to sue over patents for products made from the design. Not submitted to the OSI.
Use it if you're modifying a project that already uses it. For new projects, CERN-OHL-S v2 is the more common reciprocal choice.
Official text: the TAPR Open Hardware License.
CC BY-SA 4.0
Creative Commons Attribution-ShareAlike 4.0 International. Anyone may share and adapt the material for any purpose, including commercially, with credit, and adaptations must carry the same license.
Use it for manuals, build guides, photos and illustrations, especially alongside a reciprocal hardware license. It doesn't address manufacturing or patents, so it's a weaker fit for design files.
Official text: CC BY-SA 4.0.
CC BY 4.0
Creative Commons Attribution 4.0 International. Anyone may share and adapt the material for any purpose with credit. No share-alike requirement.
Use it for documentation that goes with a permissive hardware license.
Official text: CC BY 4.0.
Not on this list
Licenses with non-commercial (NC) or no-derivatives (ND) terms don't meet the open source hardware definition. For firmware and other software, use an open source software license such as GPL-3.0, Apache-2.0 or MIT.
This page summarizes the licenses for orientation. It's not legal advice, and the license text is what counts.