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What is a WOFF file?

WOFF is a font packaged for websites, smaller than the desktop file it came from so pages load faster. Every browser supports it, though WOFF2 is smaller again and is what most sites now serve. You can convert WOFF files here, both into the format and out of it.

Specification

WOFF format specifications
Full nameWeb Open Font Format
Extensions.woff
Media typefont/woff
CompressionLossless
Transparency
Animation
Multiple pages
Colour depthPer-table zlib compression over a TrueType or OpenType payload
Size limits
Introduced2009
Developed byMozilla, Type Supply and LettError, standardised by W3C
StandardOpen
Browser supportEvery browser, including older ones

What WOFF is used for

  • Web font delivery to browsers that predate WOFF2 support
  • Fallback in a @font-face src list behind a WOFF2 entry
  • Intranet applications standardised on older browser versions
  • Email and document templates that reference a hosted font

Strengths and limitations

What WOFF does well

  • Roughly 40 percent smaller than the TTF or OTF it wraps
  • Supported by every browser including Internet Explorer 9
  • Carries the licence details alongside the font itself

Where WOFF falls short

  • Superseded by WOFF2, which is around 30 percent smaller again
  • Larger than WOFF2, which compresses the whole font in one pass
  • Not installable as a desktop font without converting it back

Convert WOFF to

Every target this format can be written out as, each on its own page.

Convert to WOFF

Everything that can be turned into a WOFF file.

Questions about WOFF

What is a .woff file?

WOFF is a font packaged for websites, smaller than the desktop file it came from so pages load faster. The extension .woff identifies it, and its media type is font/woff.

How do I open a WOFF file?

Any current browser will open it directly, so dragging the file into a tab is usually enough. Most operating systems also preview it without extra software.

Is WOFF lossy or lossless?

Lossless. Nothing is discarded, so repeated saves never degrade the contents.

What is WOFF good for?

Roughly 40 percent smaller than the TTF or OTF it wraps. Supported by every browser including Internet Explorer 9. Carries the licence details alongside the font itself. In practice that makes it a good fit for web font delivery to browsers that predate WOFF2 support, and Fallback in a @font-face src list behind a WOFF2 entry.

What are the drawbacks of WOFF?

Superseded by WOFF2, which is around 30 percent smaller again. Larger than WOFF2, which compresses the whole font in one pass. Not installable as a desktop font without converting it back.

Other font formats

Fonts converter or the full format reference