How to Convert HEIC to AVIF in Your Browser

How HEIC becomes AVIF

1. The browser parses the HEIC/HEIF file's ISO-BMFF container and locates each embedded HEVC-coded image — a HEIC can hold more than one, such as a burst sequence or a Live Photo's paired stills.
2. Each image is decoded from its HEVC intra-frame coding into raw pixel data on an in-memory canvas, the same step your iPhone or Mac performs to display the photo.
3. The canvas pixel data is re-encoded through the browser's native AVIF encoder, which applies AV1 intra-frame coding at the quality level you choose.
4. Each result is checked for a genuine image/avif signature; a HEIC containing multiple images produces multiple AVIF files, packaged together as a ZIP.

What changes when you convert

HEIC and AVIF are architecturally siblings rather than rivals: both apply modern, block-based video-codec compression to a single still frame, which is why they both beat older formats like JPEG on file size at equivalent quality. What actually changes in this conversion is compatibility, not compression philosophy — AVIF is readable by far more non-Apple browsers, operating systems, and image tools than HEIC ever became. One thing that does not carry over: EXIF metadata, including camera settings and GPS location, is not preserved in the AVIF output.

Unlike most of the other formats in this converter family, AVIF encoding here is not a custom WASM-based encoder — it uses the browser's own built-in AVIF encoder through the canvas API. That means alpha transparency support is delegated to whatever your browser's AVIF encoder does with it, which is not a hard guarantee, and encoding reliability is strongest in Chromium-based browsers such as Chrome, Edge, and Opera; other browsers may encode more slowly or with different defaults.

If your source HEIC is a Live Photo or burst shot, every decoded image is converted — nothing is silently dropped to just the first frame, unlike several other source formats in this tool.

When AVIF is the right choice — and when it isn't

AVIF earns its place when you're publishing iPhone photos to a website or app where file size directly affects load time and you can count on a reasonably modern, Chromium-leaning audience — it typically offers the best compression-to-quality ratio of any format this tool can produce.

It's the wrong choice if you need dependable, uniformly-supported transparency or you're targeting older or non-Chromium browsers, where WebP remains the safer bet. And if the goal is preserving the photo as an unmodified archival master rather than a delivery asset, TIFF — not a lossy codec-based format — is the more appropriate target.

Limitations and privacy

Because AVIF encoding depends on the browser's built-in encoder rather than a bundled library, output quality, alpha handling, and even whether AVIF encoding is available at all can vary by browser and version. EXIF metadata from the original HEIC is not carried into the AVIF file, and a multi-image HEIC always produces one AVIF per image rather than a single merged output.

All decoding and encoding happens locally in your browser; the HEIC file is never uploaded to a server for this conversion. The tool supports files up to 25MB and 8192px per dimension.