Convert HEIC photos to AVIF in your browser

A HEIC file holds a photo encoded with the HEVC codec inside a HEIF container, defined in the ISO/IEC 23008-12 standard[1]. The iPhone 7 and later models running iOS 11 or later save photos in this format[2], and since Android 10 in 2019, so do phones with a suitable hardware encoder[1].

AVIF stores the image with the AV1 codec in the same HEIF container that HEIC uses[3]. The format is open and royalty-free, supports transparency, animation and HDR images, and according to MDN a lossy AVIF is around half the size of a JPEG at similar quality[3]. It displays in Chrome 85, Edge 121, Firefox 93, Safari 16.4 and later[4].

Among browsers, only Safari 17 and later displays HEIC files[5], and Windows opens them only when two extensions from the Microsoft Store are installed[6]. A photo converted to AVIF can go on a web page and display in current browsers, and in our measurement every AVIF file came out smaller than the original.

1. Drag your photos onto the Add files field, or click it and pick files. The converter accepts .heic and .heif files, several at once.
2. Move the Set AVIF quality slider to a value between 60 and 95 percent (default 80); the current value appears next to its name.
3. Click Convert. Each finished photo shows Done.
4. Save one file with Download or all of them with Download all, which packs several files into a ZIP archive. Only the extension changes, to .avif.

The queue shows the Before and After weight of each file with the difference in percent and, below the buttons, the totals for the batch.

Moving the slider sets finished files back to Pending, so clicking Convert again saves them with the new setting.

Everything happens in your browser: its HEVC decoder reads the HEIC photo, and the libavif library, also running in the browser, saves the AVIF.

At the default slider setting, each of the eight photos came out smaller, by 19 to 50 percent. The mixing console photo from the Samsung went from 1.16 MB to 604.2 KB, and the brick pillar photo from the iPhone from 2.70 MB to 2.14 MB. The whole batch weighed 13.1 MB as HEIC and 8.68 MB as AVIF.

The same eight photos saved with the HEIC to WebP converter at the same setting of 80 percent weighed 5.95 MB together, less than as AVIF. MDN states that AVIF usually compresses better than WebP[3]. The sliders of both converters share the same scale, but each encoder translates it into its own compression settings, so the same number gives a different weight in each format.

If you want the lightest possible AVIF file, lower the slider and look at the result zoomed in. AVIF uses lossy compression here, so at lower settings some fine detail disappears.

EXIF data does not carry over to the AVIF file, so the device model, date and location coordinates are removed with it. We checked this on the eight files from our measurement: each HEIC file had EXIF data with the device model, and none of the output files still had it.

The encoder saves the image with 8 bits per channel and without an embedded color profile. A phone photo recorded at a higher color depth gets an 8-bit version in AVIF.

MDN advises keeping a fallback version of the image in WebP, JPEG or PNG on a web page for browsers without support for this format[3]. The HEIC to JPG converter prepares one. An AVIF file you already have turns back into a JPG in the AVIF to JPG converter, photos you already have as JPG become AVIF in the JPG to AVIF converter, and smaller photo dimensions can be set in the Helios editor.