Free online OTC to OTF converter

What the OTC format is

OTC means OpenType Collection. It is an OpenType sfnt container holding two or more related fonts, such as multiple weights, styles, language variants, or regional glyph sets. Fonts in a collection can share tables, reducing storage compared with separate files.

OTC files are produced by font build systems and font editors, and are commonly encountered in large multilingual font families such as CJK releases. Operating systems and font managers may install them directly, but individual-font tools sometimes require extraction first.

What the OTF format is

OTF normally contains one font face rather than a collection. It can use CFF/CFF2 outlines or TrueType outlines; changing the filename to .otf does not change the outline technology.

Use OTF when a design, publishing, web-font preparation, or font-editing program accepts a single OpenType font. Converting a collection usually produces one OTF file per member, not one OTF file representing the entire collection.

How to convert OTC to OTF

Using FontTools

FontTools can read the collection and save every contained font as an individual OpenType file.

1. Install Python and FontTools with python -m pip install fonttools.
2. Create a file named extract_otc.py containing:

from pathlib import Path
from fontTools.ttLib import TTCollection

source = Path("input.otc")
output_dir = Path("otf-output")
output_dir.mkdir(exist_ok=True)

collection = TTCollection(str(source))
for number, font in enumerate(collection.fonts, start=1):
    destination = output_dir / f"{source.stem}-{number}.otf"
    font.save(str(destination))
    print(destination)

3. Put the script and the source file in the same directory, rename the source to input.otc, and run python extract_otc.py.
4. Find the extracted files in otf-output. Open each file in a font editor or inspect its family and style name before installing it.

Using the online converter

You can convert the file for free on 101convert.com without installing software. Upload the OTC file, choose OTF as the output format, start the conversion, and download the resulting file or files. If the service exposes collection members separately, download each member; an OTC containing several faces cannot be represented faithfully by a single ordinary OTF.

Quality, compatibility, and limitations

• Extraction normally preserves glyphs, metrics, OpenType layout tables, and font metadata, but it removes the collection container and its shared-table storage savings.
• FontTools does not automatically convert TrueType outlines to CFF outlines. The extracted file may therefore have TrueType outlines while using the .otf extension; this is valid OpenType, although some older software expects TrueType-outline files to use .ttf.
• Variable-font, color-font, or advanced CJK tables require an application with matching OpenType support. Converting the container does not make unsupported font technologies compatible.
• Keep the original OTC and verify the font license before redistributing extracted members. Some licenses permit installation but restrict modification or redistribution.