TTF vs OTF: choosing the right font format
Understand what TrueType and OpenType describe, why identical designs may ship in both, and how to choose without creating duplicate font installations.
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OTF is a container; outlines determine the practical difference
OpenType fonts can contain PostScript CFF outlines or TrueType outlines. A .ttf file usually contains TrueType outlines, while .otf commonly contains CFF outlines, but the extension alone does not prove quality. Both formats can carry Unicode mappings and OpenType layout features. Rendering quality depends on the outlines, hinting, tables, and the software using them.
Prefer the publisher’s intended desktop build
If a foundry supplies both TTF and OTF versions of the same release, install one format unless an application requires the other. Installing both can produce duplicate menu entries or unpredictable selection. Compare internal family, style, version, unique ID, glyph coverage, and outline fingerprints—not filenames alone—to decide whether two files are equivalent.
Web delivery is a different decision
Modern websites should normally serve WOFF2 generated or supplied for web use, subject to the license. Keep the original desktop font as the source artifact and avoid repeated conversions, which can discard metadata or layout tables. Test the actual characters and features your site needs, then subset only when the license permits it.