Open Source License Popularity
John T. Haller, Updated March 28, 2011 (Created August 28, 2009)
Popularity of individual open source license usage is tracked by several entities with the results published online. I thought it would be interesting to combine the license types that are similar and map out the overall popularity along with OSI and FSF approval and GPL compatibility. As you can see, the GPL/LGPL is the most popular license by a wide margin with over 60% of software being licensed under one or more versions. The next 3 licenses are all GPL compatible in some way meaning 75% to 89% or more open source code is GPL compatible (you can't tell exactly as some version issues enter into the mix with the Apache and Perl licenses).
| License | Percent | OSI Approved | FSF Approved | GPL Compatible |
|---|---|---|---|---|
| GPL/LGPL (2 & 3) | 60.91% | Yes | Yes | Yes |
| New BSD / MIT | 14.22% | Yes | Yes | Yes |
| Artistic License (Perl) | 8.49% | Yes | Yes (2 Only) | Yes (AL v2 Only) |
| Apache License | 4.85% | Yes | Yes | Yes (GPL3 Only) |
| Code Project Open License | 2.50% | No | No | No |
| Microsoft Public License (Ms-PL) | 1.72% | Yes | Partially* | No |
| Mozilla Public License (MPL) | 1.36% | Yes | Partially* | No (Unless Specified) |
| Common Public License (CPL) | 0.46% | Yes | Yes | No |
| Eclipse Public License (EPL) | 0.67% | Yes | Yes | No |
| zlib/libpng License | 0.37% | Yes | Yes | Yes |
Statistics from Black Duck Software from March 28, 2011.
* the FSF recognizes the license as a free software license but recommends against using it