What is a .ttc file?
TrueType Collection · Font · Apple / Microsoft · 1990s
TTC bundles several related fonts, most often the different weights of a large CJK typeface, into a single file that lets them share identical glyph data instead of duplicating it. It is how operating systems ship huge font families without wasting enormous amounts of disk space.
What is a .ttc file used for?
A TTC bundles several related fonts into one file while letting them share glyph data that is identical between them, most often the thousands of CJK (Chinese, Japanese, Korean) characters that look the same across a typeface's weights.
Without a collection, each weight of a big CJK font family would have to duplicate every one of those shared glyphs, so a TTC can be dramatically smaller than shipping the same fonts as separate TTF files.
The .otc extension marks the same container used for CFF/OpenType outlines instead of TrueType outlines; both are defined by the same 'ttcf' structure in the OpenType specification.
You mostly meet a TTC as a system font, macOS and Windows both ship several, rather than something you download and install yourself.
How to open a .ttc file
The .ttc format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- Windows Font Viewer (double-click)
- FontForge
macOS
- Font Book
- FontForge
Linux
- Font viewer
- FontForge
Web
- Not used directly on the web; individual fonts are extracted first
How to convert a .ttc file
You can convert a .ttc file to TTF, OTF using a conversion tool or the export menu of an app that opens it.
.ttc file signature (magic bytes)
Programs recognise a .ttc file by the bytes at the start of the file, not by its name. These are the signatures for TTC. For a full breakdown, see the TTC file signature page.
| Hex signature | Offset | Note |
|---|---|---|
| 74 74 63 66 | 0 | 'ttcf' |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .ttc file?
TTC bundles several related fonts, most often the different weights of a large CJK typeface, into a single file that lets them share identical glyph data instead of duplicating it. It is how operating systems ship huge font families without wasting enormous amounts of disk space.
How do I extract a single font from a TTC file?
FontForge can open a TTC and let you save one of the fonts inside it individually as a TTF. Some system font viewers also let you preview and install just one member of the collection.
Why is a TTC file so much smaller than expected for several fonts?
A TrueType Collection lets multiple fonts inside it share identical glyph data, most often thousands of CJK characters common across a family's weights, instead of duplicating that data in every font.
Related formats
Sources
Details on this page were checked against authoritative references: