How to ttf vs otf: what the magic bytes tell you
- Step 1Spot the magic — TTF magic 0x00010000 (or 'true'): quadratic outlines, hinted. OTF magic 'OTTO' (0x4F54544F): cubic CFF outlines, no native hinting. Both wrap the same naming, metrics, and OpenType layout tables.
- Step 2Compare file size — For Latin alphabets, OTF is typically 5–15% smaller than TTF because cubic outlines need fewer control points. For CJK and complex scripts, TTF often wins because the glyph count amortises the hinting overhead.
- Step 3Pick by audience — Web delivery: doesn't matter — both wrap into WOFF2 the same way. Desktop printing: OTF for typography quality, TTF for system-font fallback compatibility. Embedded systems: usually TTF (CFF parser is heavier).
Frequently asked questions
Does the browser care which outline format?+
No. Modern browsers render both equally well via the system text engine. CFF outlines may render slightly differently than TrueType on subpixel grids, but the difference is invisible at typical sizes.
Why does OTF have no hinting?+
CFF outlines were designed for high-resolution PostScript printers (1990s) where hinting was unnecessary. TTF was designed for 75 DPI screens of the same era where hinting made the difference between readable and unreadable text. Modern subpixel rendering removed the practical difference.
Can I convert OTF to TTF?+
Yes via desktop tools (FontForge, fonttools), but the converted TTF lacks proper hinting — it'll be rendered grayscale-only. For web delivery, just convert to WOFF2 directly; the outline format inside doesn't affect performance.
Is one format more accessible?+
No. Accessibility depends on font choice (sans-serif, x-height, weight contrast), not format. A well-designed OTF and a well-designed TTF render with identical accessibility characteristics.
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.