Convert WebP to AVIF

Convert WebP to AVIF online, free and 100% in your browser. No upload, no signup, no size limit — WebAssembly does the work on your device.

How to convert an image

  1. Drop or pick your WebP file — or paste it with Ctrl/⌘+V.
  2. AVIF is already selected as the target; tune the quality slider if you like (default 60).
  3. Convert, compare the before/after, and download — all on your device.

Why convert to this format?

WebP is a modern web format that is typically 25–35% smaller than JPG or PNG at the same quality, with transparency. AVIF is the newest AV1-based format — the smallest files of all, with transparency and wide-gamut color.

OptImg runs the same Rust codecs desktop tools use, compiled to WebAssembly, so you get desktop-grade AVIF output at a sensible default (quality 60) — adjustable at any time — without ever uploading your image.

Everything happens locally: your WebP is decoded, re-encoded to AVIF and handed straight back as a download. No server sees a single byte, which is why there's no queue and no file-size cap.

Frequently asked questions

Is my WebP uploaded to a server?
No. The WebP-to-AVIF conversion runs entirely in your browser with WebAssembly — your file never leaves your device, there is no queue, and no size limit beyond your device's memory.
Why is AVIF slower than the other formats?
AVIF uses the AV1 video codec, which trades encode time for the smallest files. Small images finish in a moment; very large photos can take a minute or more — the tool warns you first and you can cancel anytime.
Will converting WebP to AVIF lose quality?
AVIF is lossy, tuned to a visually transparent default (quality 60) that you can raise or lower with the slider. If the conversion can't produce a smaller file than your original, we hand the original back instead.
Is the WebP to AVIF converter free?
Yes — completely free, with no signup, no watermark and no cap on how many files you convert. There is nothing to install; it runs in your browser.