How to convert WebP to AVIF
Load one still WebP, set the quality, and export. There is a single quality slider running from 1 to 100 that starts at 68. That is the only encoding control: there is no lossless mode, no encoder effort setting, and no chroma or bit depth option here.
The panel shows the source alongside a preview of the encoded AVIF and reports the output size along with a percentage change. The preview is decoded back and redrawn so the comparison works even in browsers where AVIF display is unreliable.
One quirk worth knowing: setting the slider to 1 encodes at full quality rather than at 1 percent, because of how the underlying encoder interprets that value. Everything from 2 to 100 behaves as you would expect.
- Open one still WebP in the browser
- Set the AVIF quality
- Compare the preview and the size delta
- Export the AVIF locally
What you actually gain, and what it costs
AVIF is the more efficient format. Our benchmark measured AVIF at 37% smaller than JPEG at matched quality, with WebP sitting between the two. So converting WebP to AVIF does produce a smaller file, but the gain is more modest than that headline number suggests, because you are compressing something that has already been compressed once.
And that is the cost. This is a lossy-to-lossless-nothing conversion: both formats are lossy, so re-encoding one into the other discards a little more detail on the way through. If you still have the original PNG or JPG, converting from that instead is strictly better, because the image only gets compressed once.
Compatibility is the other half of the decision. AVIF support in browsers is broad now, but WebP still has wider support in desktop applications, older systems, and tooling outside the browser. Downgrading compatibility to save a few kilobytes is rarely the right call for a file that has to be opened by other people.
Transparency, animation, and browser support
The source is decoded with its alpha channel intact and handed to the encoder without being flattened, so transparency can carry through. Whether it does is up to the browser AVIF encoder, which is why the panel reports whether the source has meaningful alpha rather than promising the output will keep it. Check the result before you rely on it for a logo with a soft edge.
Animated WebP is out of scope and is rejected with a clear message rather than producing an unexpected still. Animation has different export expectations, so it belongs in the dedicated animation tools.
The converter needs a browser with modern image decoding and offscreen canvas support. Where those are missing the uploader is disabled with an explanation instead of failing halfway through an export. Encoding AVIF is also more CPU-intensive than encoding WebP, so a large image takes noticeably longer.
- Alpha is passed through unflattened, and the panel flags whether the source has any
- Animated WebP is rejected rather than silently flattened
- A modern Chromium or Safari build is required