HEIC to AVIF Converter

Two efficient formats for two different jobs

HEIC and AVIF are both modern, efficient image formats, but they are not interchangeable and they are not competitors in the same market. HEIC is what an iPhone writes, built on HEVC coding inside a HEIF container, and it is chosen to save storage on a device. AVIF is built on AV1 coding, designed for delivery over the web, and it is what you want when the image is going to be looked at by a browser. Converting between them is moving a photo from the camera to the web, not upgrading a format.

Apple Support: using HEIF or HEVC media on Apple devices

Why AVIF needs a fallback and HEIC does not

A HEIC file has no web use at all, so nothing depends on it. An AVIF file may be the only copy you have, and if a browser does not support it the image simply does not appear. That is why the standard approach is to serve AVIF and fall back to WebP, which keeps both files rather than replacing one with the other. If you can only upload a single file, WebP is the safer choice and the difference in size is modest.

• Serve AVIF with a WebP fallback where you control the markup.
• Keep the WebP versions. They are the insurance policy.
• If only one file is possible, WebP is the safer single format.
• Check that your CMS accepts AVIF uploads before converting a whole set.
• Older browsers show a broken image rather than a graceful degradation for AVIF.

What the conversion does to quality

HEIC is already lossy, so the file you are converting is a reconstruction, and AVIF will reconstruct again from that. One conversion is perfectly acceptable for web delivery, which is what this is for. What is not acceptable is round tripping: HEIC to AVIF to HEIC and back accumulates loss each time. Convert once, from the original HEIC, and keep the HEIC if you may need it again.

• One conversion from HEIC to AVIF is fine for web use.
• Convert from the original HEIC each time, not from a previous output.
• Keep the HEIC original. It is the highest quality source you have.
• Expect the AVIF to be a little smaller than the HEIC at matched quality, not dramatically.
• AVIF encoding is slower than WebP, so a large batch takes a while.

Preparing a photo library for the web

A phone library is a folder of HEIC files that no browser will display, so converting a whole shoot is a normal chore. Doing it in one pass with a single quality setting keeps the gallery consistent, which matters because a set of images at visibly different qualities looks careless. The originals stay where they are, and the converted set is what gets uploaded, so nothing is lost and the conversion is repeatable.

• Add the entire folder and apply one quality setting for consistency.
• Check a few images at 100 percent before processing everything.
• Keep the HEIC originals in case you need a different format later.
• If a site cannot use AVIF, convert straight to WebP instead rather than in two steps.