How to Convert AVIF to WebP in Your Browser

How AVIF becomes WebP

1. The browser decodes the AVIF file's AV1-based bitstream into raw pixel data, reading whatever color and alpha information the frame carries.
2. Only the first frame is decoded — AVIF can be animated, but this conversion path treats the file as a single still image.
3. The decoded pixels are drawn onto an in-memory canvas.
4. The canvas is re-encoded through the browser's native WebP encoder at the quality level you choose, producing a new file with its own compression decisions, independent of how the AVIF was originally encoded.

What changes when you convert

Unlike most conversions on this site, going from AVIF to WebP is not a reliable way to shrink a file. AVIF's compression is generally more efficient than WebP's at a matched quality level, so re-encoding an already well-compressed AVIF as WebP can land at a comparable size, or in some cases larger. The change worth expecting here is compatibility, not compression — WebP support across current browsers and image software is broader and more consistently reliable than AVIF's, particularly for encoding on the fly.

Transparency generally carries through: if the source AVIF has an alpha channel, the decoded pixels keep it, and the WebP encoder writes it into the output when your browser's implementation supports alpha, which is the common case today. Animation does not survive regardless of the source — since AVIF is capable of holding multiple frames, it's worth being explicit that only the first one makes it into the conversion, so a fully animated AVIF becomes one static WebP image.

When WebP is the right choice — and when it isn't

WebP is the safer default when an image needs to render everywhere without a fallback plan: it decodes and encodes reliably across current Chrome, Firefox, Edge, and Safari, in a way AVIF's on-the-fly encoding doesn't yet match everywhere. If your AVIF is already going onto a page or into software you know supports AVIF, converting to WebP may not gain you much — you already have a well-compressed, alpha-capable file, and re-encoding it can add a step without cutting bytes.

Keep the AVIF when compression is the priority and you control the delivery environment; convert to WebP when broad compatibility matters more than squeezing out the last few percent of file size.

Limitations and privacy

This conversion decodes AVIF only through your browser's built-in decoder, so support depends on what you're running — less common browsers may fail to open the file at all. Animated or HDR AVIF content is reduced to a single frame, and any bit depth beyond 8 bits per channel is not preserved through the canvas step.

Conversion happens entirely in your browser: the AVIF is decoded, converted, and re-encoded locally, and nothing is uploaded to a server for this workflow.