Compress OTF fonts by subsetting them

OpenType is a table file, not a compressed archive. The saving is the glyphs you drop, and this cuts them on your own machine.

OTF

No OTF selected

Drop a file to start

Drop OTF files here

or browse your device. Everything is processed on this device

No OTF to hand?

OTF options

Characters to keep Latin

Latin is ASCII plus the accented letters, typographic punctuation and currency symbols an English or Western European site renders. Latin Extended adds Central European, Turkish and Vietnamese. All keeps every glyph and saves almost nothing, which is the point of this page.

Keep hinting Off

Hinting nudges outlines onto the pixel grid. It does nothing on a Mac, a phone or any high-density screen, and Windows ClearType still uses it at small sizes. Dropping it takes another 10 to 30% off a hinted font.

Strip metadata Off

Removes version strings, trademark records, the digital signature and the screen-size tables no browser reads. The licence text and licence URL are never removed: that is a legal question, not a compression one.

Shipping to the web?

WOFF2 is about 30% smaller than WOFF for the same font, and every modern browser supports it. Convert after subsetting if you are self-hosting.

Compress WOFF2

How to subset and compress an OTF

01

Drop the OpenType font in

The sfnt tables are read in this tab. Nothing is uploaded.

02

Choose the characters you need

Latin covers an English or Western European site. Widen it if your pages carry other alphabets.

03

Check what it dropped

The result panel says how many glyphs went and what stopped working. Read it before you ship.

04

Download the smaller OTF

Keep OpenType where your toolchain expects it, or move to WOFF2 for self-hosted web use.

What compressing an OTF actually means

OTF is OpenType in an sfnt wrapper. Some files carry TrueType outlines (glyf/loca); others carry CFF PostScript charstrings under an OTTO header. Neither flavour is a compressed container, so recompressing the file alone does nothing useful.

For TrueType-outline OpenType, subsetting is the same surgery as on a TTF: keep the characters you need, follow composites, rebuild the metrics and the character map. That is routinely a huge cut on a pan-European or pan-Asian family.

CFF OpenType is different. Its outlines are a charstring program, and cutting glyphs safely needs a CFF interpreter this tool does not ship. Rather than emit a font that renders blanks, those files are refused for glyph subsetting with that reason spelled out. Metadata stripping alone is not offered as a pretend win.

On the web, prefer WOFF2 after you have the glyph set you want. It is the container browsers expect, and it is substantially smaller than raw OpenType over the wire.

OTF and font subsetting FAQ

What is the difference between OTF and TTF?

Both are sfnt fonts. TTF usually means TrueType outlines; OTF usually means OpenType, which may use TrueType outlines or CFF. The extension is a hint, not a guarantee: always trust the file header.

Why was my CFF OpenType refused?

Because subsetting CFF needs a charstring interpreter, and a partial rewrite is how you get a font that draws nothing. TrueType-outline OpenType fonts are handled in full. Convert CFF to a TrueType-outline font with a dedicated tool if you need a subset.

What is font subsetting?

Cutting the file down to the characters you actually render. The subsetter keeps those glyphs and the pieces composite glyphs need, then rebuilds the tables around them.

Will subsetting break my text?

Yes, if you remove a range you use. Missing characters fall back to another font or show as boxes. Proof your real pages, especially user input.

Should I use OTF or WOFF2 on a website?

WOFF2. Raw OTF works in some older setups, but WOFF2 is smaller and is what modern @font-face rules expect. Use this page when you need OpenType to stay OpenType.

Is it legal to subset a font I bought?

Read the licence. Open licences usually allow it; commercial webfont licences often allow subsetting for your site only. Licence text inside the file is left in place.