HEIF to SIXEL Converter

Quick HEIF to SIXEL — convert your images online for free

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Cloud-Based Engine

All conversion work happens in the cloud — no local CPU load, no memory pressure. Upload your HEIF and get the SIXEL result without slowing down your machine.

User-Friendly Tool

Upload your HEIF, pick SIXEL as the output, and click Convert — the streamlined interface makes the entire process straightforward for anyone.

Cross-Platform

No app downloads needed. The browser-based tool converts HEIF to SIXEL on Windows, Mac, Linux, iOS, and Android devices seamlessly.

How to convert HEIF to SIXEL

1

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

2

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

3

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

About formats

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
SIXEL (Six Pixel) is a bitmap graphics encoding format created by Digital Equipment Corporation (DEC) in 1983 for rendering images on character-cell printers and video terminals. The name derives from the encoding's fundamental unit: a column of six pixels represented by a single ASCII character. Each printable character in the sixel data stream (ASCII 63-126) encodes a 6-pixel vertical column, with the character's binary value determining which pixels are on or off. Color is specified through register-based palette control: a Select Color Sequence assigns an HLS or RGB color value to a numbered register, and subsequent sixel characters use that color until another register is selected. The encoding supports raster attributes for specifying pixel aspect ratio and image dimensions, repeat sequences (! followed by a count and character) for run-length compression of identical columns, and $ (carriage return) and - (new line) for navigating the sixel grid. DEC implemented SIXEL support in their VT240, VT241, VT330, and VT340 terminals, as well as multiple printer models. One advantage of the SIXEL encoding is its ASCII-clean nature: the data stream consists entirely of printable characters and standard control sequences, meaning SIXEL graphics can be transmitted through any text-based communication channel — serial terminals, SSH sessions, telnet connections — without requiring binary-safe transport or protocol modifications. The format's modern renaissance provides another remarkable dimension: after decades of obscurity, SIXEL support has been implemented in numerous contemporary terminal emulators, enabling inline image display in command-line workflows. SIXEL output can be generated by ImageMagick, libsixel, chafa, and various plotting libraries.
Initial release: 1983

Frequently Asked Questions

Why would I convert HEIF to SIXEL?

Despite HEIF's quality advantages, compatibility gaps persist on Windows and web — converting to SIXEL eliminates viewer and upload restrictions.

What applications work with SIXEL?

SIXEL works with mlterm, xterm, mintty, and other Sixel-compatible terminal emulators.

Is my HEIF file safe during conversion?

Yes — uploaded HEIF files are deleted immediately after conversion, and the SIXEL output is removed from servers within 24 hours for your privacy.

Is HEIF to SIXEL conversion free?

Yes — basic HEIF to SIXEL conversion is free. If you need to process larger batches or bigger files, premium options are available.

Can I convert multiple HEIF files to SIXEL at once?

Absolutely — Convertio lets you upload multiple HEIF files simultaneously. Each is converted to SIXEL and available for individual download.

Do I need to install software?

No software needed. The conversion engine runs server-side — you just upload your HEIF through the browser and get the SIXEL back.