The TAPR Open Hardware License

The TAPR Open Hardware License is TAPR’s contribution to the community of Open Hardware developers. TAPR grants permission for anyone to use the OHL as the license for their hardware project, provided only that it is used in unaltered form.

Download the TAPR Open Hardware License:

Format Filename MD5 Checksum
ODF TAPR_Open_Hardware_License_v1.0.odt 3b0db72c03acdc37c8a80f1d90152cff
PDF TAPR_Open_Hardware_License_v1.0.pdf d418287fd8dc7734924cb66a577cda5b
Text TAPR_Open_Hardware_License_v1.0.txt 659518fa65dbbe6958a8ad2acb2aae1a

About the OHL

The TAPR Open Hardware License (“OHL”) provides a framework for hardware projects that is similar to the one used for Open Source software. This isn’t as straight-forward as it seems because legal concepts that work well for software (such as copyright and copyleft) don’t neatly fit when dealing with hardware products and the documentation used to create them.

Here is a description, taken from the OHL’s Preamble, of how the Open Hardware License works and how to use it:

Open Hardware is a thing – a physical artifact, either electrical or mechanical – whose design information is available to, and usable by, the public in a way that allows anyone to make, modify, distribute, and use that thing. In this preface, design information is called “documentation” and things created from it are called “products.”The TAPR Open Hardware License (“OHL”) agreement provides a legal framework for Open Hardware projects. It may be used for any kind of product, be it a hammer or a computer motherboard, and is TAPR’s contribution to the community; anyone may use the OHL for their Open Hardware project. You are free to copy and use this document provided only that you do not change it.

Like the GNU General Public License, the OHL is designed to guarantee your freedom to share and to create. It forbids anyone who receives rights under the OHL to deny any other licensee those same rights to copy, modify, and distribute documentation, and to make, use and distribute products based on that documentation.

Unlike the GPL, the OHL is not primarily a copyright license. While copyright protects documentation from unauthorized copying, modification, and distribution, it has little to do with your right to make, distribute, or use a product based on that documentation. For better or worse, patents play a significant role in those activities. Although it does not prohibit anyone from patenting inventions embodied in an Open Hardware design, and of course cannot prevent a third party from enforcing their patent rights, those who benefit from an OHL design may not bring lawsuits claiming that design infringes their patents or other intellectual property.

The OHL addresses unique issues involved in the creation of tangible, physical things, but does not cover software, firmware, or code loaded into programmable devices. A copyright-oriented license such as the GPL better suits these creations.

How can you use the OHL, or a design based upon it? While the numbered sections of the agreement take precedence over this preamble, here is a summary:

* You may modify the documentation and make products based upon it.* You may use products for any legal purpose without limitation.

* You may distribute unmodified documentation, but you must include the complete package as you received it.

* You may distribute products you make to third parties, if you either include the documentation on which the product is based, or make it available without charge for at least three years to anyone who requests it.

* You may distribute modified documentation or products based on it, if you:

* License your modifications under the OHL.* Include those modifications, following the requirements stated below.

* Attempt to send the modified documentation by email to any of the developers who have provided their email address. This is a good faith obligation — if the email fails, you need do nothing more and may go on with your distribution.

* If you create a design that you want to license under the OHL, you should:

* Include the OHL document in a file named LICENSE.TXT (or LICENSE.PDF) that is included in the documentation package.* If the file format allows, include a notice like “Licensed under the TAPR Open Hardware License (” in each documentation file. While not required, you should also include this notice on printed circuit board artwork and the product itself; if space is limited the notice can be shortened or abbreviated.

* Include a copyright notice in each file and on printed circuit board artwork.

* If you wish to be notified of modifications that others may make, include your email address in a file named “CONTRIB.TXT” or something similar.

* Any time the OHL requires you to make documentation available to others, you must include all the materials you received from the upstream licensors. In addition, if you have modified the documentation:

* You must identify the modifications in a text file (preferably named “CHANGES.TXT”) that you include with the documentation. That file must also include a statement like “These modifications are licensed under the TAPR Open Hardware License.”* You must include any new files you created, including any manufacturing files (such as Gerber files) you create in the course of making products.

* You must include both “before” and “after” versions of all files you modified.

* You may include files in proprietary formats, but you must also include open format versions (such as Gerber, ASCII, Postscript, or PDF) if your tools can create them.

The TAPR Noncommercial Hardware License

The TAPR Noncommercial Hardware License has been deprecated.

Legal Background

John Ackermann’s article

explores the legal issues involved with applying open source software concepts to hardware designs. (Reproduced by permission of the University of Dayton Law Review; cite as John R. Ackermann, Toward Open Source Hardware, 34 U. Dayton L. Rev. 183 (2009)).


John Ackermann, N8UR, is the author of the TAPR Open Hardware License. John is an attorney who specializes in software licensing. He was assisted by a number of both active developers and lawyers who reviewed innumerable drafts and provided valuable feedback.

The primary review mechanism was an “OHL Development” mailing list. The members of that list include: Lyle Johnson, KK7P, Bruce Perens, K6BP, Bdale Garbee, KB0G, David Toth, VE3GYQ, Don Jackson, AE5K, Chris Day, AE6VK, Rick Hambly, W2GPS, and Darryl Smith, VK2TDS.

In February, 2007, a public comment period took place, hosted at

John would particularly like to thank Bdale Garbee, Lyle Johnson, Bruce Perens, and especially his colleagues Kirk Johnsen and Professor Robert Lech, for help that went above and beyond the call of duty.