fonttools-subset

Subset a TTF font file to the Basic Latin Unicode block

$ fonttools subset [path/to/font.ttf] --unicodes=U+0000-007F

$ fonttools subset [path/to/font.ttf] --unicodes=U+0000-007F --flavor=woff2

$ fonttools subset [path/to/font.ttf] --unicodes=U+0000-007F --layout-features=onum,kern

$ fonttools subset [path/to/font.ttf] --unicodes=U+0000-007F --output-file=[path/to/subset.ttf]

fonttools subset [options] input_font [output_font]

--unicodes=U+0041,U+0042
    Specify Unicode codepoints (hex) to include.

--unicodes-from-file=FILE
    Read Unicode codepoints from text file.

--glyphs=G1,G2
    Include specific glyphs by name.

--glyphs-from-file=FILE
    Read glyph names from text file.

--layout-features=kern,liga
    Retain OpenType layout features.

--name-languages=ENG,DEU
    Keep name table entries for languages.

--name-IDs=1,2,3
    Retain specific name table IDs.

--flavor=woff2|woff|variable
    Set output format (default: input extension).

--no-hinting
    Remove bytecode hinting instructions.

--oblique
    Add PostScript oblique angle.

--no-notdef-outline
    Omit .notdef glyph outline.

--truncate-glyph-names
    Shorten glyph names for legacy tools.

--quiet
    Suppress non-error messages.

--help-all
    Show all options.

The fonttools subset command creates optimized, smaller font files by removing unused glyphs, characters, and tables from input OpenType, TrueType, WOFF, or variable fonts. It supports specifying content via Unicode codepoints, glyph names, text files, or OpenType layout features like kerning (kern) and ligatures (liga).

Ideal for web fonts, mobile apps, and embedded uses, it reduces file sizes significantly—often by 90%—improving load times without losing rendering quality for specified text. Output supports flavors like WOFF2, variable fonts, and collections. It preserves essential tables (e.g., names, metadata) customizable via options, handles hinting, and supports advanced features like glyph name truncation for PDF compatibility.

Developed as part of the FontTools Python library, it processes fonts programmatically with high precision, supporting complex scripts and GSUB/GPOS tables.

Requires Python FontTools (>=4.0); some options incompatible with variable fonts. Always test output rendering. Large inputs may be memory-intensive.

fonttools subset input.ttf output.woff2 --unicodes=U+0041,U+0042,U+0061 --flavor=woff2
fonttools subset NotoSans-Regular.ttf --text="Hello World" --layout-features=kern,liga --flavor=woff2 output.woff2

Input: .ttf, .otf, .woff, .woff2, .ttc. Output extension or --flavor sets type; defaults to input if unspecified.

Part of FontTools library since v4.0.0 (2017); replaced legacy pyftsubset. Developed by Behdad Esfahbod/Google, actively maintained for modern font standards.

pyftsubset(1), woff2_compress(1), fontforge(1)