OTF to FAX Converter

Render OpenType font glyphs as fax-compatible images online for free

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Fax Compatible

Render OTF font glyphs directly into FAX format images that meet Group 3 fax transmission standards for telecom and document workflows.

Quick Processing

FAX images are lightweight and convert rapidly. Get your OTF glyph renderings in fax format within seconds on Convertio servers.

All Online

No fax software or specialized tools needed on your computer. Convert OTF to FAX entirely through your web browser from any device.

How to convert OTF to FAX

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose fax or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your fax file right afterwards

About formats

OTF (OpenType Font) is a scalable font format jointly developed by Microsoft and Adobe, announced in 1996 and later standardized as ISO/IEC 14496-22. OpenType unifies TrueType and PostScript font technologies under a single container — OTF files with PostScript outlines use CFF/CFF2 tables for cubic Bezier curves, while those with TrueType outlines use quadratic splines in glyf tables (these typically carry the .ttf extension despite being OpenType). The format supports up to 65,535 glyphs per font, enabling comprehensive coverage of Unicode's vast character repertoire including Latin, Cyrillic, Arabic, CJK, and mathematical symbols within one file. Advanced typographic features are encoded in GSUB (glyph substitution) and GPOS (glyph positioning) tables, powering contextual alternates, ligatures, small caps, stylistic sets, and complex script shaping. A defining advantage is cross-platform consistency — the same OTF file renders identically on Windows, macOS, Linux, iOS, and Android without platform-specific builds. The rich OpenType Layout feature system is another major strength, giving designers fine-grained typographic control that was previously impossible in a single font file. OpenType 1.8 introduced variable font technology, allowing continuous interpolation across weight, width, slant, and custom design axes within a single compact file. Universal support in web browsers, design applications, office suites, and operating systems makes OTF the dominant professional font format in modern digital typography.
Initial release: 1996
FAX is a generic image file extension associated with facsimile transmission formats standardized by the ITU-T (formerly CCITT), with the underlying Group 3 compression standard ratified in 1980. FAX files typically contain monochrome (1-bit, black and white) image data compressed using the Modified Huffman (MH) encoding defined in ITU-T Recommendation T.4, which assigns variable-length codes to run lengths of consecutive white or black pixels along each scanline. The standard resolution for Group 3 fax is 204x98 dpi (normal mode) or 204x196 dpi (fine mode), reflecting the capabilities of thermal and laser fax machines of the era. FAX files encountered digitally are often raw Group 3 encoded bitstreams or TIFF wrappers with CCITT Group 3 compression (TIFF compression tag 3). The Group 3 encoding scheme is highly efficient for typical business documents — pages with mostly white space and black text — achieving compression ratios of 10:1 to 20:1 compared to uncompressed bitmaps. One advantage is universal fax system compatibility: Group 3 encoding is the mandatory baseline for all fax machines worldwide, meaning FAX files contain data in exactly the format transmitted over telephone lines, preserving the original fax data without transcoding losses. The format's role in business communications history provides another dimension — billions of fax transmissions using this encoding moved legal documents, medical records, and business correspondence for decades, and archived FAX files represent an important documentary record. FAX images can be viewed and converted using LibreOffice, ImageMagick, GIMP, and standard document management systems.
Developer: ITU-T
Initial release: 1980

Frequently Asked Questions

Why convert OTF to FAX?

FAX format is required by fax machines and legacy telecom systems. Converting OTF glyphs creates text images compatible with Group 3 fax transmission.

How do I open a FAX image?

FAX images open in IrfanView, GIMP, and specialized fax viewer software. Windows Fax and Scan can also display and send these files directly.

Is FAX a black-and-white format?

Yes — fax images are monochrome by design, optimized for text and line art. OTF glyphs render as sharp black shapes on white backgrounds.

Can I fax the output directly?

The resulting FAX image can be loaded into fax software or sent to a fax machine. It uses the standard encoding that fax devices understand.

Is this service free?

Yes — OTF to FAX conversion is free on Convertio. Upload and convert in your browser without any cost or software.