G4 to HEIF Converter

Transform fax documents to HEIF format online free

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Format Migration

Migrate G4 files to HEIF for better accessibility — modern viewers and editors handle HEIF natively.

Any Device Works

Access the G4 to HEIF converter from desktops, laptops, tablets, and phones — fully browser-based.

Data Protection

Your G4 files are removed immediately after processing. Converted HEIF output is purged within 24 hours.

How to convert G4 to HEIF

1

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

2

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

3

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

About formats

G4 is a monochrome image format based on the ITU-T Group 4 facsimile coding standard (Recommendation T.6), ratified by the CCITT in 1984 as an improvement over Group 3 for use on error-free digital networks like ISDN rather than analog telephone lines. G4 files contain 1-bit image data compressed using exclusively two-dimensional Modified Modified READ (MMR) coding, where each scanline is encoded as a set of differences (changing elements) relative to the line above it. By eliminating the one-dimensional coding fallback and the end-of-line synchronization markers required by Group 3, G4 achieves 20-50% better compression ratios on typical document pages while producing a simpler, more regular bitstream. The format is most commonly encountered as a compression method within TIFF files (TIFF compression tag 4), where it became the standard archival format for scanned documents in enterprise document management, government records, and legal imaging systems. G4 compression is specified at 200, 300, or 400 dpi depending on the scanning application, with 300 dpi being the most common for archival-quality document imaging. One advantage is exceptional compression efficiency for document content: G4's two-dimensional prediction exploits the strong vertical correlation in text and line art pages, typically compressing a 300 dpi letter-size page to 30-50 KB — roughly half the size of equivalent Group 3 encoding. The format's entrenchment in document management infrastructure is another strength — G4 TIFF is the mandated format for many government digital records systems, court filing systems, and corporate archives, supported by every enterprise imaging platform.
Developer: ITU-T (CCITT)
Initial release: 1984
HEIF (High Efficiency Image File Format) is a container format for images and image sequences standardized by the Moving Picture Experts Group as ISO/IEC 23008-12, first published in 2015. HEIF is built on the ISO Base Media File Format (ISOBMFF, the same container used for MP4 video), providing a flexible structure that can hold single images, image collections, image sequences (like animations or bursts), and derived images with non-destructive editing operations. The container is codec-agnostic — while the most common implementation pairs HEIF with HEVC/H.265 compression (branded as HEIC by Apple), the standard also accommodates AV1 compression (creating the AVIF variant), H.266/VVC, and other future codecs. HEIF supports features that JPEG lacks: 10-bit and 12-bit color depth, wide color gamuts (Display P3, BT.2020), lossless compression, alpha transparency, depth maps, thumbnail images, and Exif/XMP metadata — all within a single file. Auxiliary image items can store computational photography data like depth maps, HDR gain maps, and semantic segmentation masks. One advantage is the format's future-proof architecture: by separating the container from the codec, HEIF can adopt newer, more efficient compression technologies without changing the file structure, metadata handling, or application-level APIs. The substantial compression improvement over JPEG is another core strength — HEVC-based HEIF typically achieves 40-50% file size reduction compared to JPEG at the same visual quality, beneficial for storage and bandwidth. HEIF is supported by Apple's ecosystem (iOS, macOS), Windows 10/11, Android 10+, GIMP, ImageMagick, and Adobe products.
Initial release: 2015

Frequently Asked Questions

Why convert G4 to HEIF?

Digitizing fax files to HEIF format enables easy viewing, sharing, and embedding across modern platforms.

What can open HEIF format?

View HEIF files with Apple devices natively, Windows with HEIF extension, or GIMP — all handle this format natively.

Does converting G4 degrade quality?

The HEIF output faithfully reproduces all content from the G4 source — quality is not compromised.

Can I use this converter at no cost?

Free for regular use. Premium plans unlock faster conversion speeds and larger batch processing limits.

Is multi-file G4 conversion supported?

Yes, batch processing works. Upload as many G4 files as needed and each becomes a separate HEIF output.

Does the converter work on mobile devices?

Yes — the G4 to HEIF converter is fully responsive. It works on phones, tablets, and any device with a browser.