Font Subsetter
Reduce font file size online for free by keeping only the Unicode characters your page actually uses. Our font subsetter supports TTF, OTF, WOFF, and WOFF2 files — select a character set preset or paste your page text to auto-extract unique characters. Critical for Core Web Vitals. No signup, no server uploads, 100% private.
Why Use Our Font Subsetter?
Instant Font Subsetting
Our font subsetter analyzes your font file and extracts only the glyphs you need — entirely in your browser. No upload wait times, no server queues. Subset fonts in seconds and see exact glyph counts and estimated size savings instantly.
Secure Font Subsetter Online
Your font files never leave your device when you use our font subsetter online. 100% client-side processing means complete privacy — no server uploads, no font data retention, no licensing exposure from uploading proprietary typefaces.
Font Subsetter Online — No Installation
Subset fonts directly in your browser with no software downloads, no Node.js setup, and no command-line tools required. Our font subsetter works on any device with a modern browser — desktop, tablet, or mobile.
Core Web Vitals Impact
Font subsetting is one of the highest-impact optimizations for Core Web Vitals. Reducing a 200 KB font to 20 KB eliminates render-blocking delays, improves LCP scores, and reduces cumulative layout shift caused by font swap flashes.
Common Use Cases for Font Subsetting
Web Performance Optimization
Use our font subsetter to reduce web font payload sizes and eliminate render-blocking font requests. A subsetted font loads 60–90% faster than the full typeface, directly improving your Largest Contentful Paint (LCP) score and Core Web Vitals.
CMS & WordPress Sites
Subset fonts before self-hosting them on WordPress, Ghost, or any CMS to avoid Google Fonts GDPR concerns. Our font subsetter lets you keep only the characters your content actually uses, reducing font file size by up to 90% for English-only sites.
React & Next.js Apps
Optimize font loading in React and Next.js applications by subsetting fonts to only the characters used in your UI. Smaller font files reduce JavaScript bundle impact and improve Time to Interactive (TTI) for single-page applications.
Mobile App Development
Reduce font asset sizes in React Native, Flutter, and native iOS/Android apps. Subsetted fonts reduce APK and IPA bundle sizes, improve app store download rates, and decrease memory usage on low-end devices.
Email Template Design
Subset custom fonts for HTML email templates to stay within email client size limits. Smaller embedded font files improve email load times and reduce the chance of Gmail clipping your email due to message size limits.
Design System Delivery
Subset brand fonts for design system packages and component libraries. Shipping only the glyphs used in your design system reduces npm package size, speeds up CI/CD pipelines, and keeps your design tokens lean.
Understanding Font Subsetting
What is Font Subsetting?
Font subsetting is the process of creating a smaller version of a font file that contains only the glyphs (individual character shapes) you actually need. A full typeface like Roboto contains over 1,000 glyphs covering Latin, Cyrillic, Greek, and extended Unicode ranges. If your website only uses English text, you need fewer than 100 glyphs. Our font subsetteranalyzes your font file, identifies which glyphs map to your requested characters via the font's cmap table, and produces a minimal subset — reducing file size by 60–95% without any visual change to your rendered text.
How Our Font Subsetter Works
- Upload your font file: Drag and drop or click to browse. Our font subsetter accepts TTF, OTF, WOFF, and WOFF2 files. Your font never leaves your browser — all processing is 100% client-side.
- Select your character set: Choose a preset (Basic Latin, Latin + Punctuation, Latin Extended) or paste your actual page text to auto-extract the exact unique characters your site uses. The tool shows you the precise glyph count and estimated size reduction before you download.
- Download your subset font:Click "Subset Font" to analyze the font and generate size estimates, then download the subset file. Use it as a drop-in replacement for the original font in your CSS
@font-facedeclaration.
What Gets Removed During Font Subsetting
- Unused Glyphs:Character shapes for languages and scripts you don't use — CJK (Chinese, Japanese, Korean), Cyrillic, Arabic, Devanagari, and hundreds of other Unicode blocks are stripped from the font binary.
- Unused OpenType Features: Ligature tables, kerning pairs, and alternate glyph sets for removed characters are eliminated, reducing the GSUB and GPOS table sizes significantly.
- Unused Glyph Metrics: Advance width, side bearing, and hinting data for removed glyphs are stripped from the hmtx and cvt tables.
- Redundant Name Records: Extended font name table entries for unused language localizations are removed, trimming the name table overhead.
Important Notes About Font Subsetting
WOFF2 fonts use Brotli compression which requires server-side decompression for full subsetting — our browser-based tool provides analysis and size estimates for WOFF2 files but recommends converting to TTF first for full subsetting. Always verify your subsetted font renders correctly across all browsers before deploying to production. If your content is dynamic (user-generated text), use a broader character set preset to avoid missing glyphs at runtime.
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Frequently Asked Questions About Font Subsetter
A font subsetter is a tool that creates a smaller version of a font file containing only the glyphs (character shapes) you actually need. Instead of loading a full 200 KB typeface with 1,000+ glyphs, a subsetted font might be 15–30 KB with only the 80–100 characters your site uses. Our font subsetter runs entirely in your browser — no server uploads required.
Font subsetting typically reduces file size by 60–95% depending on the original font and your character set. A full Latin + CJK font like Noto Sans can be reduced from 15 MB to under 50 KB for an English-only site. Even Latin-only fonts like Roboto can be reduced from 150 KB to 20–30 KB by keeping only the characters you use.
Yes, completely. Our font subsetter processes everything locally in your browser. Your font files are never uploaded to any server, never stored, and never transmitted over the network. This is especially important for proprietary or licensed typefaces where uploading to third-party servers could violate your font license.
Yes. This font subsetter is 100% free with no signup, no premium tier, no watermarks, and no file size limits. You can subset as many font files as you need with no restrictions.
Our font subsetter supports TTF (TrueType), OTF (OpenType), WOFF (Web Open Font Format), and WOFF2 files. TTF and OTF provide the most accurate subsetting results. WOFF files are supported with full analysis. WOFF2 files use Brotli compression which requires server-side tools for full subsetting — our tool provides analysis and size estimates for WOFF2.
For English-only sites, "Latin + Punctuation" covers everything you need. For Western European multilingual sites, use "Latin Extended" to include accented characters like é, ü, ñ. For the most precise subset, paste your actual page text into the scanner — the tool extracts exactly the unique characters your content uses, nothing more.
Yes — if a character is not in the subset, the browser will display a fallback glyph (usually a box or the system font). For static content like headings and UI labels, this is not a concern. For user-generated content or search inputs, use a broader preset like "Latin Extended" or keep the full font for those specific elements.
Use the subsetted font exactly like the original in your @font-face declaration — just replace the font file URL with the path to your subset file. You can also add a unicode-range descriptor to tell the browser exactly which characters the subset covers, enabling the browser to load the font only when those characters appear on the page.
Font subsetting removes unused glyphs from the font binary, reducing the number of characters the font can render. Font compression (like WOFF2) applies Brotli or zlib compression to the remaining data without removing any glyphs. For maximum size reduction, you should both subset the font and serve it in WOFF2 format — subsetting first, then converting to WOFF2.