The short version
- Converting doesn't change the license. A font you may not use on a website can't be used there as WOFF2 either.
- Licenses are split by use. Desktop, web, app and e-book use are often sold separately.
- Some licenses forbid modification, and some count format conversion or subsetting as modification.
- Open licenses are the easy case. Fonts under the SIL Open Font License can be converted and used on the web.
This page explains common licensing terms. It isn't legal advice, and your own license agreement always takes priority over anything here.
Kinds of font license
- Desktop
- Install the font on a set number of computers and use it in documents, images and print. Usually doesn't cover putting the font file on a website.
- Webfont
- Serve the font from your website, often limited by page views or domains. Usually doesn't cover installing it on a computer.
- App and e-book
- Bundle the font inside software or a publication. Often a separate license again.
- Open source (OFL)
- The SIL Open Font License allows use, embedding, conversion and modification, with one notable condition about names, below.
The embedding setting inside every font
Font files carry a small setting, chosen by the font's maker, that says how the font may be embedded in documents. Technically it is the fsType field of the font's OS/2 table. Refont reads it from every file you convert:
- Installable
- No embedding restriction. Most open fonts use this.
- Editable
- May be embedded in documents that others can edit.
- Preview and print
- May be embedded only for viewing and printing. Refont shows a caution.
- Restricted
- The maker asks that the font not be embedded at all without permission. Refont shows a warning.
Two more parts of the setting can say "don't subset this font" and "embed only as bitmaps". These matter mostly to PDF and office software.
The setting is a hint, not the license. It was designed for document embedding, many makers set it carelessly, and it can't express webfont or app terms. A font marked Installable can still have a license that forbids conversion, and the reverse also happens. Read the license agreement that came with the font.
Fonts from websites
WOFF and WOFF2 files you can see in a website's code belong to that site's license, which covers serving them on that site. Downloading them and converting them for your own use is generally a license violation, even though nothing technically stops it. If you like a font you saw on a site, find out what it is and get it from its foundry or a free alternative.
Open fonts and Reserved Font Names
Most fonts on Google Fonts use the SIL Open Font License (OFL), which allows conversion and web use. Some OFL fonts declare a Reserved Font Name: modified versions may not use that name. Whether a plain format conversion or a subset counts as a modified version is discussed in the official OFL FAQ at openfontlicense.org; read it if you plan to redistribute a converted OFL font under its original name.
What Refont does
Refont shows the embedding setting for every file and warns when it is Restricted or Preview and print. It never blocks a conversion, because only you can see your license agreement, and many legitimate uses (converting a font you designed, or one your license explicitly allows) would otherwise be impossible. Your fonts are never uploaded, so using Refont also doesn't put a copy of a licensed font on anyone else's server.