FB2 to G3 Converter

Convert FB2 to Group 3 fax images — free online

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Fax Standard Format

G3 is the international fax compression standard — convert FB2 pages into format that any fax system can process.

Private Conversion

FB2 uploads are deleted instantly after processing. G3 output files are removed from servers automatically within 24 hours.

Web-Based Tool

No fax software or command-line tools needed. Handle the entire FB2 to G3 conversion through your web browser.

How to convert FB2 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

FB2 (FictionBook) is an XML-based ebook format created by Dmitry Gribov in 2004, designed to provide a clean semantic description of a book's content independent of its visual presentation. Unlike page-layout formats, FB2 encodes structure — title, authors, chapters, annotations, genres, epigraphs, poems, footnotes, and binary attachments (typically cover images) — within a single well-formed XML document. This structural approach means reading applications have full control over rendering, allowing the same file to adapt perfectly to a small phone screen or a large e-ink reader. FB2 became enormously popular in Russia and Eastern Europe, serving as the dominant format on major Russian digital libraries and ebook distribution platforms. One significant advantage is metadata richness: the format's schema mandates detailed bibliographic information including author, translator, series position, publication date, and genre classification, making library management and discovery straightforward. The plain-text XML foundation is another strength — FB2 files are human-readable, easy to validate, and simple to transform using standard XML tools like XSLT. The format specification is freely available on GitHub, and a wide ecosystem of readers, editors, and converters supports it across all major platforms, from desktop applications like Calibre to dedicated e-readers with native FB2 rendering.
Developer: Dmitry Gribov
Initial release: 2004
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 FB2 to G3?

G3 is the ITU standard for fax encoding. Converting FB2 to G3 produces pages compatible with fax systems and document imaging tools.

How is G3 different from FAX format?

Both use Group 3 compression. G3 is the raw encoding standard, while FAX is a container variant — both work with fax equipment.

What opens G3 files?

ImageMagick, IrfanView, and fax software suites handle G3 files. They can also be sent directly through internet fax services.

Is it free?

Yes. FB2 to G3 on convertio.tools is completely free — no payments, no registration, no trial restrictions.

Are G3 images monochrome?

Yes — Group 3 encoding is strictly black-and-white, optimized for text documents and line art transmission over fax lines.