CMX to G3 Converter

Convert CMX to G3 online — Group 3 fax output free

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Fax Standard

G3 is the international fax compression standard. CMX to G3 conversion makes your Corel designs transmission-ready.

Web-Based Converter

No fax software installation needed. Convert CMX to G3 directly in your browser from any device and operating system.

Rapid Results

G3 images are small and simple. Conversion from CMX happens almost instantly — upload and download in seconds.

How to convert CMX to G3

1

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

2

Choose g3 or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your g3 file right afterwards

About formats

CMX (Corel Presentation Exchange) is a vector graphics exchange format developed by Corel Corporation, introduced with CorelDRAW 5 in September 1994. Designed as a cross-application interchange format within the Corel product suite, CMX stores vector objects, text, bitmaps, and rendering attributes in a structure accessible to CorelDRAW, Corel PHOTO-PAINT, Corel Presentations, and other Corel applications without requiring each program to understand the full CDR native format. The format uses a chunk-based architecture that encodes geometric primitives, fill patterns, outline properties, and color definitions in a standardized way, supporting both 16-bit and 32-bit variants. CMX gained significance beyond the Corel ecosystem through its adoption by third-party applications and its role in clipart distribution — many vector art collections from the mid-to-late 1990s shipped in CMX format. One advantage is interoperability within design workflows: CMX provided a practical bridge for moving vector content between different Corel applications while preserving visual fidelity, gradients, and transparency attributes. The format's inclusion of both vector and bitmap data within a single file is another strength, allowing complex mixed-media illustrations to be exchanged as self-contained units. Microsoft also added CMX import support to some Office applications, expanding the format's reach. While modern Corel applications primarily use CDR for native work and export to SVG, PDF, or EPS for interchange, CMX files from the CorelDRAW era remain widely encountered in legacy asset libraries.
Developer: Corel Corporation
Initial release: 1994
G3 is a monochrome image format based on the ITU-T Group 3 facsimile coding standard (Recommendation T.4), ratified by the CCITT in 1980 as the universal compression method for fax transmission over telephone networks. G3 files contain 1-bit (black and white) image data encoded using Modified Huffman (MH) one-dimensional coding, where each scanline is independently compressed by replacing runs of consecutive white or black pixels with variable-length codewords from a predefined Huffman table optimized for typical document content. The standard also defines an optional two-dimensional coding mode (Modified READ) that encodes each line as differences from the previous line, achieving better compression for pages with vertical redundancy. Standard G3 resolution is 204 pixels per inch horizontally and either 98 (standard) or 196 (fine) pixels per inch vertically, producing the characteristic slightly-stretched appearance of received fax documents. The encoding was carefully optimized for the real-time transmission constraints of 1980s modems operating at 2400 to 14400 bps, where encoding and decoding speed had to match the communication channel rate. One advantage is universal telecommunications compatibility: Group 3 encoding remains the mandatory baseline codec for every fax machine manufactured, ensuring that G3 image data can be transmitted to or received from any fax device worldwide. The format's efficiency for document content is another strength — the Huffman tables were statistically tuned to the run-length distributions found in business documents, and typical pages compress to under 30 KB. G3 files are supported by LibreOffice, ImageMagick, and fax server software.
Developer: ITU-T (CCITT)
Initial release: 1980

Frequently Asked Questions

Why convert CMX to G3?

G3 is the ITU Group 3 fax compression format. Converting CMX to G3 prepares your Corel designs for standard fax machine transmission.

What uses G3 files?

Fax machines and fax server software use G3 encoding. Software like HylaFAX and most fax gateways handle G3 images natively.

Is G3 monochrome?

Yes — G3 fax compression encodes black-and-white images. Your CMX design is rendered in monochrome for fax transmission.

How long does conversion take?

G3 files are compact, so conversion finishes almost instantly on Convertio cloud servers.

Is there a charge?

No — basic CMX to G3 conversion is free. Premium plans provide additional capacity for business fax workflows.