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PDF Font Subsetting

Reduce PDF file size by subsetting embedded fonts — keeping only the glyph data actually used in the document and removing unused characters. Effective for PDFs with large embedded font sets.

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How to Use PDF Font Subsetting
  1. 1Upload the PDF you want to reduce by subsetting its fonts
  2. 2The tool analyses embedded fonts and identifies unused glyph data
  3. 3Review which fonts will be subsetted and the expected size reduction
  4. 4Click 'Subset Fonts' to apply
  5. 5Download the PDF with smaller embedded font files
Examples
  • Reduce a PDF using a full Unicode font by subsetting to only the characters actually used
  • Shrink a multilingual document that embeds large CJK fonts down to used glyphs only
  • Optimise a branded PDF that embeds a full custom typeface by subsetting unused characters
  • Reduce file size of a PDF using an Arabic font where only a few glyphs appear in the document
Frequently Asked Questions

When a PDF embeds a full font file, it includes data for all characters in that font (often thousands of glyphs). Subsetting removes all glyph data for characters not actually used in the document, keeping only what is needed.

It depends on how many characters from each font are used. A document using only Latin characters from a CJK (Chinese/Japanese/Korean) font file can save several MB. For typical Western text, savings are smaller (50–200 KB per font).

Yes. Only unused character data is removed. All text visible in your document uses the retained glyphs and will display correctly in all PDF viewers.

Yes. If someone adds text using a character that was removed during subsetting, that character may not display correctly. Only subset fonts in final/archived versions.

No. Embedding includes the full font in the PDF. Subsetting includes only the portion of the font needed for the actual characters in the document.

Yes. All processing runs in your browser. Your PDF is never uploaded to any server.

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