What is the TTF file format?
.ttf is a font file format storing TrueType font definitions. TrueType is a font standard developed by Apple in the late 1980s and introduced with System 7 in 1991. Due to its popularity, both Windows and macOS support it natively.
The introduction of TrueType was a major breakthrough in computer font technology. Until then, most systems used bitmap fonts, which weren't scalable and did not look good in print. TrueType offered fonts based on quadratic Bézier curves, which allowed for scalability and retained font quality even in print and on screen. Internally, a .ttf uses the sfnt binary container with named tables for outlines (glyf), character mapping (cmap), metrics (hmtx), and bytecode hinting instructions. A single font can hold up to 65,535 glyphs.
TrueType fonts, saved as .ttf files, are ubiquitous and regarded as one of the most popular font formats. The popularity of this format is due to many features it offers, including:
- no loss of quality when resizing (scalability),
- pixel-precision rendering through a built-in hinting system,
- perfect print fidelity,
- support for external devices (plotters, printers, cutters, etc.).
The popularity of the .ttf standard is also largely due to its adoption across the Windows family of operating systems. Today it forms the outline foundation of many OpenType fonts, while WOFF and WOFF2 wrap the same data with compression for web delivery.
Security & safety
RISK: LOWA TTF is font data, not executable code, so it's safe to install in normal use. Two real cautions: font rasterizers (in the OS kernel, browsers and PDF readers) have a long CVE history of being exploited by malformed fonts, so only install fonts from reputable sources and keep your system patched. And mind licensing/embedding: the OS/2 table's fsType flags whether a font may be embedded or installed, and many 'free' fonts are free only for personal use - commercial use may need a license. Beware sketchy 'free font' sites whose downloaders bundle adware; download the .ttf directly or use a known foundry / Google Fonts.
Format details
in a nutshellPrograms that open TTF files
Windows3 apps
FontForge
Open-source Open the .ttf to inspect/edit glyphs and metrics; File > Generate Fonts to export TTF/OTF/WOFF. 
FontCreator
Paid Open and edit the .ttf (glyphs, kerning, hinting) in a polished Windows font editor.
Windows Font Viewer / Install (built-in)
Built-in Double-click the .ttf to preview it, then click Install (or right-click > Install for all users). 
macOS2 apps
Font Book (built-in)
Built-in Double-click the .ttf to preview, then click Install Font; manage and validate fonts in Font Book. 
Linux2 apps
Install to ~/.fonts or /usr/share/fonts
Built-in Copy the .ttf to ~/.local/share/fonts (or /usr/share/fonts) and run fc-cache -f to register it.
GNOME Fonts / FontForge
Open-source Double-click in GNOME Fonts to preview/Install, or open in FontForge to edit.
Transfonter / online font tools
Free Upload a .ttf to preview it and convert to WOFF/WOFF2 (or vice versa) client-side. Technical details
deep spec| Container format | sfnt (table directory + tagged binary tables) |
| Byte order | Big-endian |
| Magic bytes | 00 01 00 00 at offset 0 (sfnt version 1.0 - TrueType outlines) |
| MIME type | font/ttf (also application/x-font-ttf, application/font-sfnt) |
| Glyph outline type | Quadratic Bézier curves (TrueType rasterizer) |
| Hinting system | Bytecode instruction language stored in cvt, fpgm, and prep tables; enables pixel-precise rendering at small sizes |
| Max glyphs per font | 65,535 (16-bit glyph index) |
| Units per em (UPM) | Typically 1,000 or 2,048; maximum 16,384 |
| Typical file size | 20 KB - 30 MB; Latin fonts are small, large CJK fonts may reach tens of MB |
| Integrity mechanism | Per-table checksums plus a whole-font checkSumAdjustment field in the head table |
| Key internal tables | glyf (outlines), cmap (char→glyph), hmtx (metrics), head, name, OS/2, post, cvt/fpgm/prep (hinting) |
| Color font support | Optional COLR/CPAL tables (layered color) or sbix/CBDT tables (embedded bitmap/PNG) |
| Embedding permissions | fsType field in the OS/2 table flags embedding rights; no encryption is applied |
| OpenType relationship | TrueType is the outline technology in many OpenType fonts; a .ttf may also carry OpenType layout tables (GSUB, GPOS) |
| Platform support | Windows, macOS, Linux, Android, iOS - installs natively without conversion on all major systems |
| Web delivery | Raw .ttf works in browsers; WOFF and WOFF2 wrap the same sfnt data with compression for faster web transfer |
| Released | TrueType: 1991 (Apple System 7); cross-platform standard through the 1990s |
| Latest version | Specification folded into OpenType (ISO/IEC 14496-22, 'Open Font Format'); current edition 2019 |
| Open standard | Yes · royalty-free |
| Specification | learn.microsoft.com |
TTF conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about TTF files.
Frequently asked questions
How do I install a TTF font?
fc-cache -f. The font then appears in your apps.What's the difference between TTF and OTF?
How do I convert a TTF to WOFF2 for my website?
Why won't my TTF install or show up in my app?
fc-cache -f).
