OTF to WOFF Converter
FileFlip converts OTF to WOFF entirely inside your browser, using the font engine compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an OTF file to WOFF?#
- Drop your OTF file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to WOFF and the conversion starts on its own. FileFlip downloads nothing at all, because everything it needs is already built into your browser, then runs the font engine on your own machine.
- Save the WOFF file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting OTF to WOFF lose quality?#
No. The glyph outlines are converted between outline models rather than redrawn, so the letterforms in the WOFF file are the ones in the OTF file. What can change is the hinting and the OpenType tables around them.
Is it safe to convert OTF files online?#
Yes, because nothing is uploaded. FileFlip converts OTF files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What OTF to WOFF actually does to the file#
Converting OTF to WOFF runs on the font engine, downloads nothing at all, because everything it needs is already built into your browser, converts the glyph outlines between outline models, keeps hinting and kerning, and drops OpenType features.
| Engine | the font engine |
|---|---|
| Conversion path | One step: OTF → WOFF |
| Downloaded to your browser | Nothing. Your browser already has everything this conversion needs |
| Quality | Outlines preserved |
| You get back | One file |
| Where it runs | On the page's own thread, so a very large file will make the tab wait |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Hinting | Kept | Carried through into the converted file. |
| Kerning | Kept | Carried through into the converted file. |
| OpenType features | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- this conversion runs on the page's own thread, so a large file will freeze the tab while it works
What is an OTF file?#
An OTF file stores a font's glyph outlines as PostScript-style cubic Bezier curves, along with the OpenType layout tables that drive ligatures and other typographic substitutions.
Use OTF for a font that relies on OpenType features like ligatures or stylistic alternates, which professional design and publishing software reads natively.
Convert OTF to WOFF2 before using it on a website, since browsers need a compressed web font format and OTF isn't one.
What is a WOFF file?#
A WOFF file wraps a TrueType or OpenType font in a compressed container built specifically for loading with @font-face on the web.
Serve WOFF when a site's browser support has to reach back further than WOFF2 covers, or as the fallback source in a @font-face src list.
Convert WOFF to WOFF2 as the primary web font and keep WOFF only as a fallback, since WOFF2 is smaller for the same font on every modern browser.
OTF to WOFF questions people ask#
Can OTF fonts be converted back from other formats?
Not with every tool. Some font converters, including this one, can read an OTF file and write it out as TTF, WOFF or WOFF2, but can't write a new OTF file, because reconstructing CFF cubic outlines from a different source isn't supported by every font engine. Turning a WOFF or TTF file into a genuine OTF usually needs a dedicated font editor instead.
Does converting OTF to another format change its license?
No, and it doesn't grant new permissions either. A font's license governs how it can be used and distributed regardless of which container format it's stored in, so a font licensed for desktop use only doesn't become licensed for web embedding just because it was converted to WOFF2.
What's the difference between OTF and TTF?
OTF adds an option for PostScript-style cubic Bezier outlines and OpenType's layout tables, like ligatures and language-specific substitutions, on top of the same font structure TTF uses. A TTF file can't hold those layout features; an OTF file can, whether its outlines are cubic or the same quadratic type TTF uses.
Why is WOFF smaller than a plain TTF file?
WOFF wraps the same TrueType or OpenType glyph data inside a zlib-compressed container, which typically shrinks the file by more than 40 percent. Decompression happens once when the browser loads the font, so the smaller download comes at essentially no runtime cost.