How to plan font glyph budgets for performance targets
- Step 1Set a per-page budget — Total page weight budget × font allocation (typically 5–10%). For a 1 MB page budget, fonts get 50–100 KB. Split across body + heading + code = 30–40 KB each on average.
- Step 2Project subsets per font — Run Glyph Count Analyser for each candidate font. Find the largest subset that fits in your per-font budget. If even Latin Basic exceeds budget, the font is too heavy — pick a different one.
- Step 3Document the budget — Pin in design system docs: 'Body font: Inter Latin subset, 22 KB max. Heading font: Inter Latin Extended, 28 KB max.' CI fails if WOFF2 output exceeds the budget.
Frequently asked questions
What's a typical font weight per page?+
Industry median: 50–100 KB total fonts. Premium brands (extensive custom typography): 150–250 KB. Performance-focused (system stacks + 1–2 web fonts): under 30 KB. Match your budget to your priorities.
Should I count Google Fonts CDN bytes?+
Yes — bytes are bytes. Self-hosting reduces overhead (one less DNS, one less TLS) but doesn't reduce font weight. Apply the budget regardless of host.
What about variable fonts in budget calc?+
Variable fonts replace multiple static files. Compare the variable file size vs the sum of static equivalents. Variable wins for 3+ weights from same family — Glyph Count + Variable vs Static Comparator together give the full picture.
Privacy first
Every JAD Font tool runs entirely in your browser using opentype.js and the wawoff2 WASM Brotli encoder. Your fonts never leave your device — verified by zero outbound network requests during processing.