The SIL Open Font License (OFL) in Plain English

The SIL Open Font License is the most important license in free typography. The large majority of Google Fonts use it, most quality free fonts released in the last fifteen years use it, and most of the DaFontFonts catalog uses it. It is also short, readable, and widely misunderstood. Here is what OFL 1.1 actually says, in plain English.

What the OFL is

The Open Font License was published by SIL International, a nonprofit language organization, in 2005, with the current version 1.1 released in 2007. It was written specifically for fonts (unlike general software licenses) by people who wanted fonts to spread freely while protecting the author’s name and keeping derivatives open.

The license is about one page long. Its core grant: anyone can use, study, copy, merge, embed, modify, redistribute, and sell the font, subject to two conditions we will get to. “Anyone” includes businesses, and “use” includes commercial use. There is no personal/commercial split anywhere in the OFL.

What the OFL permits

Everything on this list is explicitly allowed, for free, forever:

• Commercial use of every kind. Client work, products for sale, advertising, packaging, broadcast. The license draws no line between personal and commercial projects.
• Logos and trademarks. You can set your company name in an OFL font and register the result as a trademark. You own your logo; the author keeps owning the font.
• Web embedding. Serving the font to browsers via @font-face and WOFF2 is standard, licensed use. Self-hosting is fine (it is how DaFontFonts recommends you ship webfonts).
• App and game embedding. Bundling the font inside an iOS, Android, desktop, or game binary is permitted. The OFL’s redistribution terms are satisfied as long as the font is not sold by itself.
• Print, ebooks, and documents. PDFs with embedded fonts, printed books, merchandise: all covered.
• Modification. You can edit the font: subset it for performance, add glyphs, convert formats, or fork it into a new typeface. This is why performance-focused derivatives and extended language versions of popular fonts exist legally.

If your entire relationship with a font is “download it and design with it”, the OFL places zero obligations on you. No fee, no credit, no registration.

The two real restrictions

1. You cannot sell the font files by themselves

The OFL forbids selling a font “by itself”. You cannot put Montserrat in a zip and charge for the zip. You can charge for things made with it, and you can include the font in a larger product that is sold (a design bundle with other assets, a piece of software, a game). The line is: is the customer paying for the font alone? If yes, that sale violates the license.

This is also why sites that charge “download fees” for OFL fonts are violating the license, while DaFontFonts, which gives them away with the license attached, is exactly the distribution model the OFL was written for.

2. Reserved Font Names apply when you modify

If you redistribute the font (modified or not), the copyright notice and license text must travel with the files. And if you modify the font, your version cannot be named using any Reserved Font Name the author declared.

Reserved Font Names, with an example

A Reserved Font Name (RFN) is the author’s way of protecting their font’s identity. It is declared in the copyright line, for example: “Copyright 2010 The Example Project Authors, with Reserved Font Name ‘Example’.”

Here is how it works in practice. SIL’s own Gentium typeface declares “Gentium” as an RFN. If you take Gentium, add three glyphs, and want to share your version, you cannot call it “Gentium Improved” or “MyGentium” or anything containing “Gentium”. You must pick a new name (the well-known derivative distributed with modified builds is called “Gentium Plus” only because SIL, the RFN holder, released it; an outside modifier would need a clean name).

The purpose is quality control by reputation: when a user installs a font called Gentium, they know it is the real thing, not someone’s broken fork. RFNs never affect using a font, only naming a modified redistributed version of it. Note also that not every OFL font declares an RFN; many fonts on Google Fonts have had RFNs removed by their authors specifically to make subsetting and self-hosting derivatives simpler.

OFL vs Apache 2.0 for fonts

A minority of free fonts use the Apache License 2.0, a general software license, instead of the OFL. For a font user the practical differences are small; both permit commercial use, embedding, and modification with no fees. The differences that exist:

• Copyleft. OFL derivatives must stay under the OFL. Apache derivatives can be relicensed, including into proprietary products.
• Selling alone. OFL forbids selling the files by themselves. Apache does not.
• Naming. OFL has the RFN mechanism. Apache relies on trademark law instead.
• Patent grant. Apache includes an explicit patent license; the OFL does not mention patents (this matters to lawyers more than to designers).

The trend has been toward the OFL: Open Sans, originally released under Apache 2.0, was relicensed to OFL 1.1. For your day-to-day work the answer is the same under either license: use it commercially, freely.

Common myths, corrected

“I have to credit the font in my design.” No. The OFL requires no attribution in documents, websites, logos, videos, or products. Copyright and license notices must stay with the font files when the files are redistributed; your artwork is not the font files.

“There are royalties eventually.” Never. The OFL grants its permissions free of charge, permanently, worldwide. No pageview tiers, no unit counts, no renewal.

“I can’t use it in a logo because I don’t own the font.” Trademark protects your mark, not the underlying typeface, so this distinction does not restrict you. Setting your wordmark in Lato or Playfair Display is fully permitted.

“OFL fonts can be revoked.” The license is irrevocable for any copy you have received. An author can stop distributing a font or change the license on future versions, but the version you downloaded stays licensed to you under the terms it shipped with.

“Free means low quality.” The OFL catalog includes fonts commissioned by Google, Adobe, Mozilla, JetBrains, and independent foundries doing their best work in the open. Inter, Fira Code, and Merriweather are OFL.

Where DaFontFonts fits

Every OFL font on DaFontFonts links to this guide, states its license on the font page, and ships with its license text in the download, which is what the OFL asks of a distributor. If you want to browse only open-licensed type, every category on the site already qualifies: from cursive fonts to monospace fonts, everything here is OFL, Apache 2.0, UFL, MIT, or CC0. See the licenses hub for how we verify, or the font licenses overview for how the OFL compares to the rest of the licensing world.