Convert WebP to AVIF. Smaller still, without uploading
If you already serve WebP and want to squeeze pages further, AVIF is the next step down in file size: built on the AV1 video codec, it typically beats WebP at the same visual quality, especially at lower quality settings where it degrades more gracefully. This tool decodes your WebP and re-encodes it as AVIF with an AV1 encoder compiled to WebAssembly, running entirely in your browser. Both formats support alpha, so transparency is preserved. Fair warning: AVIF encoding is CPU-intensive, so large images take a few seconds each. Worth it for the bandwidth saved on a busy site.
How it works
- Drop .webp files below. Batches are welcome.
- Set the AVIF quality; 50–65 already looks excellent.
- Download each .avif once encoding finishes.
Frequently asked questions
Is AVIF really smaller than WebP?
Usually, yes. AVIF’s AV1-based compression tends to edge out WebP at matching quality, with the gap widest at aggressive settings. Results vary by image, so the before/after sizes are shown for each file.
Do browsers support AVIF?
All major browsers now do: Chrome since 2020, Firefox since 2021, Safari since version 16 in 2022. For the widest possible reach across old desktop apps, WebP remains the safer bet, but for the web itself, AVIF is ready.
Is transparency kept?
Yes. Both WebP and AVIF support full alpha transparency, and it carries over unchanged.
Are my images uploaded during conversion?
No. Decoding the WebP and encoding the AVIF both happen locally via WebAssembly. Nothing is transmitted. You can watch the network tab or go offline after loading to confirm it.