Font File Size Analyzer

A font file size analyzer is a tool that reads the binary structure of a font file and reports its internal composition — including table count, glyph count,OpenType features, and compression opportunity. Font files in TTF and OTF format are uncompressed sfnt containers made up of named tables (glyf, cmap, GSUB, head, etc.), each storing a different aspect of the font data. Our font file size analyzer parses these tables directly in your browser using the File API — no server upload, no font editing software required. WOFF and WOFF2 files are also supported, and the analyzer detects whether the font is already compressed.

1. 1Upload your font file:Drag and drop any TTF, OTF, WOFF, or WOFF2 font file onto the drop zone. The font file size analyzer reads the file binary using the browser's File API — no data is sent to any server.
2. 2Instant browser-based analysis: The font file size analyzer detects the font format from the file signature, parses the sfnt table directory, reads the name table for metadata, parses the GSUB table for OpenType features, and reads maxp/head for glyph count and units-per-em.
3. 3Review the analysis report: See file size, format, glyph count, table breakdown with visual size bars, OpenType feature tags, script support, font metadata, and estimated WOFF2/WOFF compression savings — all in one report.

• File Size & Format: The exact file size in bytes and the detected format (TTF, OTF, WOFF, WOFF2, or TTC) based on the binary signature — not just the file extension.
• Glyph Count & Table Breakdown: The total number of glyphs from the maxp table, and a visual breakdown of every sfnt table by size — showing which tables (glyf, CFF, GSUB, etc.) consume the most space.
• OpenType Features & Scripts: All feature tags registered in the GSUB table (liga, kern, smcp, onum, etc.) and all script tags — showing which writing systems the font supports.
• Compression Opportunity: Estimated WOFF2 and WOFF savings based on typical Brotli and DEFLATE compression ratios for font data — with a clear recommendation on whether to convert.

TTF/OTF are uncompressed sfnt containers — the largest format, used for desktop installation. WOFF wraps the same sfnt data with DEFLATE compression, typically 20–25% smaller than TTF. WOFF2 uses Brotli compression with font-specific preprocessing, typically 30–40% smaller than TTF and 15–20% smaller than WOFF. For web delivery, WOFF2 is the recommended format — it is supported by all modern browsers and provides the best compression. Use the font file size analyzer to confirm your current format and quantify the savings before converting.