HEIC to AVIF
Re-encode a HEIC as AVIF. Same HEIF container, a different codec inside, so the size barely moves and old software still refuses the result.
Runs on your device. The file is never uploaded.
HEIC to AVIF swaps the codec inside the HEIF container, HEVC for AV1, and both files stay ISO Media. What you gain is a format browsers display without an add-on. Nothing is rewrapped: the photo is decoded to pixels and encoded again, a second lossy generation over an image that was already lossy.
Questions
Does HEIC to AVIF upload my files?
No. HEIC to AVIF runs inside this browser tab, in a Web Worker on your own machine, and no part of your file is sent anywhere. There is no upload step to skip — the tool cannot reach a server even if it wanted to, and the counter on the homepage shows the number of outbound requests the page has made: zero.
How many files can I use at once?
Drop as many as you like. Each file is handled separately and comes back as its own result, so twenty files in means twenty results out.
What can I change about the result?
One setting: quality (Quality 1-100). Defaults are filled in, so it runs without changing anything.
Is HEIC to AVIF free, and do I need an account?
It is free and there is no account, no sign-in and no quota. Nothing is metered because nothing runs on a server — the only limit is your own device's memory, which is what decides how large a file it can handle.
Does it work offline?
Yes. The whole site is stored in your browser after the first visit, so HEIC to AVIF keeps working with the network off. Tools that use a machine-learning model download that model once, on first use, and run offline afterwards.
Can I use HEIC to AVIF outside the browser?
Yes. Every tool here is the same code on three surfaces: this page, a CLI command, and an MCP tool an AI agent can call. `heic-to-avif` is the name it goes by on all three.