WOFF File — What It Is and What Opens It

What WOFF is

WOFF is a binary format, meaningful only to a program that knows it. It is used for the web.

The extension is .woff, and the full name is Web Open Font Format. Both matter less than what the file can hold, which is what the rest of this page is about.

Where WOFF came from

W3C published it in 2009. The specification is WOFF 1.0.

Age is worth knowing here for one practical reason: the older a format is, the more programs have had time to learn it.

The specification is public

Anyone can implement it without asking permission or paying a licence, which is why it turns up in so many programs and why files written twenty years ago still open.

It is a legacy format

It still opens everywhere and is still written by older tools, but nothing new is being built around it. Convert what you mean to keep, and do not choose it for something starting today.

Nothing is thrown away

WOFF stores its content exactly. Saving it again changes nothing, so it can be opened, edited and re-saved as often as you like without accumulating damage — which is what makes it a working format rather than a delivery one.

What opens WOFF

FontForge and fonttools read it, and so do most programs of the same kind.

If a file will not open, the format is rarely the problem — it is more often that the program predates it. Converting to something older is the reliable way past that, and it is what the rest of this site is for.

Opening it in a browser

Every current browser reads it.

That makes it a safe thing to put on a page or attach to a message without wondering what the other end has installed.

It is a delivery format

WOFF is meant to be handed over rather than worked in. Editing one is possible and rarely pleasant; the sane approach is to change the source and export again.

The facts, in one place

Identifiers and provenance for the WOFF format.
Extension	.woff
Media type	font/woff
Published by	W3C
First published	2009
Specification	WOFF 1.0

What is a WOFF file?