Format at a glance
- Full name
- OpenType Font
- File extensions
- .otf
- MIME types
- font/otf
- Category
- Fonts
- Compression
- Depends on the contained codec
- Transparency
- Not applicable
- Animation
- Not applicable
- Properties
Suitable tools
What is this format?
OpenType was developed by Microsoft and Adobe and provides a unified table model for fonts. Layout tables can control ligatures, alternates, kerning and complex writing systems.
An .otf file commonly contains CFF or CFF2 outlines, while .ttf often uses quadratic TrueType outlines. Both can provide OpenType layout features.
What is it used for?
- Desktop publishing and professional typography
- System and application fonts
- Multilingual fonts with OpenType features
- Source material for webfont creation
Which programs can open it?
- Windows Font Viewer
- macOS Font Book
- FontForge and Glyphs
- Adobe and Affinity applications
Support across devices and browsers
Windows can preview and install OTF as a system font.
Font Book validates, installs and manages OTF.
Fontconfig, desktop font viewers and FontForge support OTF.
System font management is restricted, while design apps may import OTF.
Fonts can be installed through profiles or supported applications.
Websites usually prefer WOFF or WOFF2, although browsers may also load OTF as a web font.
Advantages
- Rich typographic layout features
- Cross-platform support
- Scalable vector outlines and Unicode mappings
Disadvantages
- Large character sets can produce large files
- Licences may restrict embedding or conversion
- Not every application supports every OpenType feature
Comparison with alternatives
TTF commonly uses TrueType outlines; both types may contain OpenType tables.
WOFF2 is compressed for the web and usually preferred there over OTF.
WOFF packages font data for browsers but is less compact than WOFF2.
LocalFileLab support
OTF is recognized as an input. Font tables and outlines are analysed locally.
OTF is not currently a verified LocalFileLab output.
LocalFileLab can compress OTF locally or package it in a supported archive; already compressed content will not necessarily become smaller.
A complete OTF preview is not currently available.
Complete preservation of format-specific metadata is not guaranteed.
Related formats
Frequently asked questions
Is OTF better than TTF?
Not inherently. Outline quality, hinting, character coverage and the concrete OpenType features matter more than the extension.
Can OTF be used in a browser?
Many browsers load OTF, but WOFF2 and WOFF are normally better suited to websites.
May an OTF font be converted?
Often technically yes, but only when the font licence permits modification and embedding.