What happens when you convert OTF to WOFF
- Each table of the OTF font is compressed and wrapped in a WOFF header. The glyphs, kerning, hinting and OpenType features inside are unchanged.
- WOFF is for websites: load it with @font-face in CSS. It cannot be installed on a computer, so keep the OTF for that.
How to convert OTF to WOFF online
- Press "Choose OTF files" and select one or more files, or drag them onto the box. You can add files of any size your device can hold in memory.
- There are no settings to choose: the converter keeps everything the target format can hold.
- Press "Convert to WOFF". Fonts convert instantly; nothing extra needs to download.
- Save each WOFF with its download button. Close the tab and every trace of the files is gone from memory.
Why convert OTF to WOFF?
OTF files usually come from professional typography, ligatures and design work. People convert them to WOFF because WOFF is the compressed font format every browser loads, so web pages download fonts faster.
In short, OTF is good at what it was made for, and WOFF is the more practical choice when the file has to open, upload or print somewhere else. OTF installs on Windows, Mac and Linux; browsers load it through CSS, while WOFF loads in every browser through CSS; cannot be installed on a computer.
How to convert OTF to WOFF on Windows, Mac, iPhone and Android
On Windows
Open this page in Chrome, Edge or Firefox, drag your OTF files in from File Explorer, and press Convert. Each WOFF is saved to your Downloads folder.
On a Mac
Safari, Chrome and Firefox all work. Drag the OTF files from Finder onto the drop zone and the WOFF files land in Downloads.
On iPhone and iPad
Open the page in Safari and tap Choose OTF files. You can pick from Photos or from the Files app. The converted WOFF appears in Files, in the Downloads folder.
On Android
Open the page in Chrome, tap Choose OTF files and pick them from Files or your gallery. The WOFF is saved to the Download folder, where any file manager can find it.
Best settings for OTF to WOFF
Font conversion has no quality settings, because nothing is re-drawn: the same glyph tables are packed or unpacked.
To use the WOFF on a website, upload it next to your CSS and reference it in an @font-face rule. Check the font licence first: many desktop licences do not allow web embedding.
OTF vs WOFF: the differences
| OTF | WOFF | |
|---|---|---|
| Full name | OpenType font | Web Open Font Format |
| Type | font | font |
| Created by | Microsoft and Adobe | the World Wide Web Consortium |
| First released | 1996 | 2009 |
| Compression | Lossless | Lossless |
| What it holds | glyph outlines, usually cubic PostScript curves, plus typographic features | the tables of a TrueType or OpenType font, each compressed |
| In a browser | installs on Windows, Mac and Linux; browsers load it through CSS | loads in every browser through CSS; cannot be installed on a computer |
| Common uses | professional typography, ligatures and design work | fonts served by websites |
| MIME type | font/otf | font/woff |
About OTF and WOFF files
What is an OTF file?
OpenType extends TrueType with advanced typography such as ligatures and alternate glyphs. An .otf file usually holds PostScript-style cubic outlines rather than TrueType curves.
What is a WOFF file?
WOFF is a TrueType or OpenType font with each table compressed and a small header added, which makes web fonts smaller to download. The font inside is unchanged.
OTF to WOFF not working? Common problems
- The font will not install. WOFF files cannot be installed; convert them to TTF or OTF first.
- The web font does not show. Check the path in your @font-face rule and that the server sends font files, which some hosts block by default.
- The converter says the file is not a font. Only single fonts are supported; font collections (.ttc) and WOFF2 files are not.
Convert OTF to WOFF from the command line
The fontTools library for Python converts between font and web font formats:
python3 -c "from fontTools.ttLib import TTFont; f = TTFont('input.otf'); f.flavor = 'woff'; f.save('output.woff')"The converter on this page does the same job in your browser, without installing anything.
OTF to WOFF converter FAQ
Will I lose quality converting OTF to WOFF?
No. The font data is compressed or decompressed losslessly; every glyph is identical.
Why is the WOFF a different size from the OTF?
A WOFF is usually 30 to 60 percent smaller than the font inside it, because each table is compressed.
Are my OTF files uploaded anywhere?
No. The conversion runs inside this browser tab using code on this page that repacks the font tables, so your files stay on your device. You can disconnect from the internet after the page has loaded and it still works.
Can I convert several OTF files to WOFF at once?
Yes. Select or drop as many files as you like; they are converted one after another and each gets its own download button.
How do I open a WOFF file?
WOFF loads in every browser through CSS; cannot be installed on a computer. WOFF is common for fonts served by websites.
Is this OTF to WOFF converter free?
Yes. There is no sign-up, no watermark and no limit on how many files you convert. The site is paid for by advertising, and because conversions run on your device there is no server cost per file.
Can I convert OTF to WOFF on my phone?
Yes. The converter works in Safari on iPhone and iPad and in Chrome on Android. Converted files are saved to the Downloads folder.