WOFFer – WOFF font converter

WOFF font file icon This handy tool converts TTF or OTF fonts to WOFF format and back to TTF or OTF.


Note: This app uses cutting-edge web technologies. If it behaves strangely, please try using a recent version of Chrome or Firefox.

Important: Only convert fonts that you have confirmed to have the license to do so.

How To Use

  1. Drag and drop WOFF, TTF, or OTF fonts into the box at the top of the page, or click the Choose Files button.
  2. Be patient, especially when converting TTF or OTF to WOFF. (See below for why)
  3. Download your converted files, either individually or in one zip file.


The WOFFer is a tool to convert TTF or OTF to WOFF and back to TTF or OTF. WOFF, short for Web Open Font Format, is a special font format that is compressed and optimized for use on the web. This format compresses the font data using zlib, which can greatly reduce the size of the font for faster loading.

This tool is powered by WOFFjs, a JavaScript implementation of an encoder and decoder for WOFF fonts. Your fonts are not sent to any server. Instead, they processed entirely inside your browser. You don’t need to worry about crashing my server or violating the terms of your font license, as all of the work is done locally.

Conversion to the WOFF format with this tool may be slow, because it uses Google’s Zopfli algorithm to compress the font data, yielding smaller files but a much longer conversion time.

If this tool helped you or saved you some time, you can donate to encourage further development of programs like this.

Known Issues

  • Large fonts will crash the conversion process. If a font is “processing” for too long and the font is more than a couple megabytes, you have probably run into this issue. I am working on a way to handle large fonts.
  • Safari refuses to download converted fonts for unknown¬†reasons.