What Is a WOFF File?

A WOFF file (Web Open Font Format) is a compressed font file designed specifically for web delivery. Open a WOFF file in a text editor and you'll see binary data — it's not a font you install on your computer like a TTF. It's a format meant to be served over HTTP and loaded by a browser rendering a web page.

Understanding what WOFF files are, how they differ from TTF and OTF, and when to use WOFF vs WOFF2 is useful for any web developer or designer who works with custom fonts.

What Is Inside a WOFF File

A WOFF file is not a different kind of font — it's a different container for the same font data. Specifically, a WOFF file contains:

• The compressed glyph outlines from the original TTF or OTF source (either TrueType or PostScript/CFF outlines)
• The font's metadata tables — name, licensing, kerning, unicode coverage, and so on
• A small WOFF-specific header with the original file size and compression info

The compression uses zlib — the same algorithm used in gzip — and typically produces a file 40–60% smaller than the equivalent TTF. The browser decompresses it transparently when rendering text.

The glyph data itself is identical to the source font. Rendering quality, OpenType feature support, and character coverage are all preserved.

WOFF vs TTF vs OTF — When to Use Each

TTF (TrueType Font) — a desktop font format developed by Apple and Microsoft. Works in operating systems, design applications, and @font-face CSS. No compression. Larger file sizes. Use TTF when you need to install a font on a computer or open it in a design application.

OTF (OpenType Font) — an extension of TTF developed by Adobe and Microsoft. Supports more advanced typographic features (ligatures, small caps, stylistic alternates). Also uncompressed. Use OTF for the same scenarios as TTF — desktop use, design applications.

WOFF — take a TTF or OTF, compress it, wrap it in the WOFF container format. Use WOFF when serving fonts on the web via @font-face. Supported by all browsers including IE9+.

The rule of thumb: TTF and OTF are for desktop use. WOFF (and WOFF2) are for web delivery.

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WOFF vs WOFF2 — What's the Difference

WOFF2 is a newer version of the format that uses Brotli compression instead of zlib. Brotli achieves better compression ratios on structured binary data like font outlines — WOFF2 files are typically 20–30% smaller than their WOFF equivalents.

WOFF2 is supported in all modern browsers (Chrome 36+, Firefox 39+, Safari 10+, Edge 14+). For sites where legacy browser support matters, the standard approach is to provide both:

@font-face {
  font-family: 'MyFont';
  src: url('/fonts/myfont.woff2') format('woff2'),
       url('/fonts/myfont.woff')  format('woff');
}

Modern browsers use WOFF2. Older browsers fall back to WOFF. Either way the font looks identical.

For new projects targeting modern browsers, WOFF2 alone is a reasonable choice. For maximum compatibility, serve both.

How to Convert a Font to WOFF

If you have a TTF or OTF file and need WOFF for web use, the WildandFree Font Converter converts it directly in your browser. Drop the file, select WOFF as output, download the result. No install, no account, no server upload.

Supported conversions: TTF → WOFF, OTF → WOFF, WOFF → TTF, WOFF → OTF, and between TTF and OTF in either direction.

For WOFF2 output, the standard tool is fonttools (Python):

pip install fonttools brotli
python3 -m fonttools ttLib.woff2 compress yourfont.ttf

This produces yourfont.woff2 alongside the original.

Can You Install or Open a WOFF File as a Desktop Font

Sort of. Modern versions of Windows 10+, macOS 10.12+, and most Linux distributions can install WOFF files directly — the operating system decompresses them on the fly. You can usually just double-click a WOFF file and click Install.

However, some older applications and design tools don't handle WOFF reliably for desktop use. If you need to use a font in Photoshop, Illustrator, or similar software, TTF or OTF is more dependable than WOFF.

If you have a WOFF file and need a TTF for desktop use, convert it back with the font converter — WOFF → TTF is a supported direction.

Frequently Asked Questions

Is a WOFF file the same as a TTF file?

They contain the same font data but in different containers. WOFF is a compressed wrapper around the TTF or OTF data. A WOFF file is smaller than its TTF equivalent and is designed for web delivery rather than desktop installation.

Can I open a WOFF file in Photoshop or Illustrator?

Older versions of Adobe applications don't support WOFF. For reliable use in design software, convert the WOFF back to TTF or OTF first. The font converter handles WOFF → TTF and WOFF → OTF.

What is WOFF2 and is it better than WOFF?

WOFF2 uses Brotli compression instead of zlib, making files 20–30% smaller than WOFF. All modern browsers support WOFF2. For new web projects, prefer WOFF2. For legacy compatibility, serve both WOFF2 and WOFF in your @font-face declaration.