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.
What opens 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
Open a .ttc file step by step
- Confirm the file really is a .ttc. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with Windows Font Viewer (double-click) or FontForge.
- On Mac, use Font Book or FontForge.
- On Linux, try Font viewer or FontForge.
- Still stuck? Convert the .ttc to TTF, which opens more widely.
Why can't I open my .ttc file?
Almost always because no installed app understands TTC. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .ttc at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
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.
What is the .ttc file signature (magic bytes)?
A .ttc file starts with the hex bytes 74 74 63 66, which read as ttcf in ASCII. Programs identify TTC by those bytes, not by the filename, so a renamed file still gives itself away.
These are the documented signatures for TTC. For a full breakdown, see the TrueType Collection file signature page.
| Hex signature | Offset | ASCII | Note |
|---|---|---|---|
| 74 74 63 66 | 0 | ttcf | '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
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