March 24, 20262 min read

Font Subset — Reduce Font File Size by Removing Unused Glyphs

Subset fonts to include only the characters you need. Dramatically reduce web font size for faster page loads.

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A typical font file contains thousands of glyphs for dozens of languages, but most websites use only a fraction of them. Font subsetting strips out the characters you do not need, often reducing file size by 70-90%. Use the MyPDF Font Subset tool to create lean, fast-loading web fonts.

How to Subset a Font

  1. Upload — Drop your font file (TTF, OTF, WOFF, or WOFF2) into the tool.
  2. Configure — Select the character ranges to keep: Latin, Cyrillic, Greek, CJK, or enter a custom Unicode range or text string.
  3. Download — Save the subsetted font in your preferred output format.

Size Savings by Character Set

SubsetTypical Characters KeptSize Reduction
Latin Basic~200 glyphs80-90% smaller
Latin Extended~600 glyphs60-70% smaller
Latin + Cyrillic~900 glyphs50-60% smaller
Full CJK20,000+ glyphsMinimal savings
Custom text stringOnly used charsMaximum savings

Practical Tips

  • Subset then convert. Subset the source OTF/TTF first, then convert to WOFF2 with the OTF to WOFF2 or TTF to WOFF converter for the smallest possible file.
  • Include punctuation and symbols. Do not forget currency signs, arrows, and special punctuation your content uses.
  • Use unicode-range in CSS. Pair subsetted font files with the unicode-range descriptor in @font-face so browsers only download the subset they need for a given page.

Will subsetting break ligatures or kerning?

The tool preserves OpenType layout features (ligatures, kerning, contextual alternates) for the characters included in the subset. Features involving removed glyphs are cleaned up automatically.

Can I subset a variable font?

Yes. The tool retains all variation axes and named instances while removing unused glyphs from the subset output.

How do I know which characters my site uses?

Inspect your site content or use a tool like glyphhanger to crawl pages and generate the exact Unicode range needed. Then paste that range into the custom subset field.

  • Font Preview — Preview subsetted fonts to verify glyph coverage.
  • Font Metadata — Check naming and licence info in font files.
  • OTF to WOFF2 — Convert subsetted fonts to WOFF2 for the web.
  • TTF to WOFF — Convert subsetted fonts to WOFF format.
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