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Convert WebP to AVIF

Files never leave your device. All processing happens in your browser.

Lower means a smaller file. Above 90 the file grows fast for little visible gain.

Pixels. Leave empty to keep the original dimensions.

How to convert WebP to AVIF

  1. 1

    Add the WebP files you want to compress further.

  2. 2

    Set the quality — around 50 for photographs.

  3. 3

    Compare the AVIF size against the WebP before downloading. Sometimes it is not worth it.

This is a conversion between two modern formats, which makes it the most situational one on this site. WebP is already good. AVIF is better on photographs and worse on some other things. Unlike converting from JPEG or PNG, the answer here is genuinely "check the number before you commit".

Where AVIF wins

On photographic content, AVIF beats WebP by roughly 20–30% at matched visual quality. The gap widens on large images, images with lots of smooth gradient, and images with fine noise-like texture. If your pages are dominated by big hero photographs and product shots, converting the WebP library to AVIF is a real, measurable win.

Where WebP holds its own

  • Small images. AVIF carries a few hundred bytes of container overhead, so for icons and thumbnails under a few kilobytes the AVIF can come out larger.
  • Flat graphics and text. WebP has a dedicated lossless mode that is extremely good at large single-colour areas and sharp edges; AVIF has no equivalent advantage there.
  • Decode speed. AVIF is slower to decode than WebP, which matters on low-end phones rendering many images at once.
  • Encode speed. WebP encodes in milliseconds; AVIF takes seconds. If you are processing thousands of images, that difference compounds.

You are stacking two lossy passes

Unless your WebP is lossless, it has already discarded detail, and AVIF will now compress the result — preserving the WebP artifacts faithfully and sometimes spending bytes to do so. If you still have the original PNG or camera file, converting from that instead will give you a smaller and cleaner AVIF than routing through WebP. Use this tool when the WebP is what you have, not when it is a step you chose.

Practicalities

The first conversion downloads a 3.5 MB WebAssembly encoder, because no browser can create AVIF itself. It is cached afterwards. Encoding then takes several seconds per image. Transparency carries across intact — both formats support a full alpha channel — and animated WebP converts to its first frame only, since animation is not handled by this path.

Deployment advice

Do not replace your WebP files with AVIF; add them. Serving both inside a <picture> element lets each browser take the best format it supports, and gives you a safe path back if AVIF turns out to be slower to decode on the devices your visitors actually use. Measure on a real mid-range phone rather than a desktop before rolling it out everywhere.

Encoding runs in a background thread on your own machine. No image is transmitted at any point.

Questions about WebP to AVIF

Is AVIF always smaller than WebP?

No. On photographs it is usually 20 to 30 percent smaller, but on small icons, flat graphics and images with sharp text WebP frequently wins. The result size is shown before you download so you can check case by case.

Should I replace my WebP files with AVIF?

Add rather than replace. Serving both in a picture element lets each browser pick what it handles best and leaves you a fallback. AVIF also decodes more slowly, which can matter on low-end phones with many images on screen.

Does converting between two lossy formats hurt quality?

Yes, a little. The WebP has already discarded detail and AVIF compresses what remains, preserving the existing artifacts. If you still have the original PNG or camera file, converting from that gives a better result.

Is transparency kept?

Yes. Both WebP and AVIF store a full alpha channel, so transparent and semi-transparent areas convert without any change.

What happens to an animated WebP?

Only the first frame is converted. Animated AVIF exists but producing it is a different job from still image encoding and is not what this tool does.

Why does this take seconds when WebP conversion is instant?

AVIF encoding comes from the AV1 video codec and is deliberately expensive — it works much harder to produce a smaller file. The first run also downloads a 3.5 MB encoder, since browsers can display AVIF but cannot create it.

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