How to subset a font
Load a supported font, choose the glyphs to keep, then inspect the subset and report before downloading them. Font Subsetter accepts requests entered as pasted text, Unicode ranges / code points, or Glyph names. The results show missing requests and structural validation issues.
- Drop a supported font onto Drop a font here, or choose browse files.
- Enter at least one request in Text / characters to keep, Unicode ranges / code points, or Glyph names.
- Select Also strip GSUB/GPOS/kern layout tables to save extra space only when those features are unnecessary.
- Select Compress to build the subset and show the results.
- Review warnings for missing characters, glyph names, or range entries.
- Choose Download subset font and Download report to save the outputs separately.
Enter text, Unicode ranges, or glyph names
Text / characters to keep turns pasted text into one request per unique character. Newline, carriage return, and tab characters are ignored. For example:
Input: Hello World! 123
Requests: H, e, l, o, space, W, r, d, !, 1, 2, 3Unicode ranges / code points accepts comma-separated entries such as U+0041-005A and U+20AC. Glyph names accepts comma-separated names such as dollar, at, and ampersand. A glyph name keeps the glyph without adding a Unicode mapping.
Enter at least one non-empty selection request. The results list missing characters, missing glyph names, and unrecognized range entries.
What the subset keeps and removes
The output keeps requested glyphs, the .notdef glyph, and component glyphs needed by composite glyphs. Every glyph slot stays in place. Unused glyf outlines are emptied, so the glyph count remains unchanged even when the subset file is smaller.
Layout tables are preserved by default. Select Also strip GSUB/GPOS/kern layout tables to remove existing GSUB, GPOS, kern, and GDEF tables. The page warns that removing them can break ligatures and kerning for retained glyphs.
Which font files Font Subsetter can process
TTF and TrueType-outline OTF files that use glyf outlines can be subsetted. CFF OTF files can be inspected for coverage information, but automatic subset building is unavailable for that outline format. WOFF and WOFF2 files are not accepted by the file picker.
Read subset results and validation
Subset results show original size, subset size, reduction, characters kept, glyph names kept, dependency glyphs auto-added, and layout tables preserved or stripped. Validation reparses the output, checks the glyph count, checks loca ordering and bounds, and checks table checksums. Download subset font stays disabled when validation fails, while Download report remains available.
Use a subset in a page build
Paste the characters used on a page into Text / characters to keep, then download the subset font for the page build.
Enter a Unicode block in Unicode ranges / code points, review missing code points, and keep the report with the test asset.
When the needed glyph is known by name, enter it in Glyph names. Names such as dollar and ampersand do not create Unicode mappings.
When to use Font Compress Tools
Choose Font Subsetter when you need to select characters, ranges, or glyph names. Choose Font Compress Tools when you want to reduce a font file without making those selections.
Frequently asked questions
How do I subset a font by text?
Paste the source text into Text / characters to keep, select Compress, and review the kept characters and warnings. Repeated characters become one request, while newline, carriage return, and tab characters are ignored.
Can I subset a font with Unicode ranges?
Yes, enter comma-separated values such as U+0041-005A or U+20AC in Unicode ranges / code points. Malformed, reversed, surrogate, and out-of-range entries appear as unrecognized. A range is skipped when its end is more than 20,000 code points after its start.
Can I subset a font by glyph name?
Yes, enter comma-separated names in Glyph names. A found name keeps its glyph, but it does not create a Unicode mapping for that glyph.
Why can't I compress a CFF font?
CFF fonts can show coverage information, but automatic subset building is unavailable for their outline format. The supported build path requires TrueType glyf outlines.
Does Font Subsetter upload the font?
No network upload is used for the font. The script reads, parses, subsets, and validates it in the browser with FileReader.