WebP to AVIF converter
Convert WebP files to AVIF inside this page. No upload, no limit on how many, no watermark.
- 0 uploads
- No limits
- No signup
- Works offline
If you have already moved a site from JPEG to WebP and the images are still the heaviest thing on the page, AVIF is the next step down. It compresses roughly a third better than WebP at the same perceived quality, keeps transparency, and holds together at low bitrates where WebP starts to look plasticky. It is a delivery-side optimisation: browsers read it, most other software does not, and encoding takes noticeably longer than the format you are leaving behind.
When you actually need this conversion
- Your images are already WebP and page weight is still the limiting factor on load time.
- You are storing a large library long-term and a further third off the total is worth the encoding time.
- You need aggressive compression without the smeared look WebP develops at low quality settings.
What to watch out for
- Encoding is slow — several seconds for a large image, against a fraction of a second for WebP. Plan a batch as something you leave running.
- You are re-encoding an already-lossy file. Convert from the best source you have rather than from a WebP that was itself squeezed hard.
- Support outside browsers is thin. Keep the WebP if anything in your workflow has to open the file directly.
WebP and AVIF, side by side
| WebP | AVIF | |
|---|---|---|
| Released | 2010 | 2019 |
| Compression | both | both |
| Transparency | yes | yes |
| Animation | yes | yes |
| Support | all current browsers; patchy outside them | all current browsers; limited elsewhere |
How the conversion works here
Your file is decoded in a Web Worker inside this browser tab — by the browser's own image pipeline where it can, and by a WebAssembly build of libheif or libavif where it cannot. The decoded pixels are then re-encoded with libavif, the same encoder Squoosh uses.
All of that happens on the processor in front of you. There is no upload step, no queue and no server, which is why there is no size cap, no daily allowance and no paid tier — and why the whole thing keeps working with the network switched off.
Doing more than one thing
Most people converting a format also need it smaller or a different size. The result screen hands your converted files straight to the compressor or the resizer in one click — no second download, no re-selecting files. If you need several formats, the general converter lets you pick the output each time.
How it works
- 01Add your WebP filesDrop them on the page, click to browse, paste from the clipboard, or drop a whole folder.
- 02Conversion runs on your deviceEach file is decoded and re-encoded as AVIF by a WebAssembly codec in a background thread. Nothing is uploaded.
- 03Adjust if you need toMove the quality slider — 90 is visually indistinguishable from the source for most photographs.
- 04DownloadSave one file, or take the whole batch as a zip built on your device.