Convert WebP to AVIF

Free, in your browser — your image never leaves you. Alpha transparency is preserved.

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RoundCut converts WebP to AVIF entirely in your browser. The file is never uploaded. Alpha transparency is preserved, since both formats support it. AVIF is typically 20 to 30 percent smaller than the equivalent WebP at the same perceptual quality. Encoding takes a few seconds on large images and pays a one-second WASM cold start on the first conversion.

How to convert WebP to AVIF

Drop a WebP file on the upload area (or click to pick one). The conversion runs the moment the file lands — there is no "Convert" button to chase. The first conversion in a session loads the AVIF encoder, which takes about a second of WASM cold-start; subsequent conversions in the same tab skip that step and finish faster. When the result is ready, the stats line shows the input and output size, and the Download button saves the AVIF file to your device with the same base name as the original.

How much smaller is AVIF than WebP?

AVIF builds on the AV1 video codec and reaches roughly 20 to 30 percent smaller files than WebP at the same perceptual quality, per measured SSIM and DSSIM comparisons across photo test sets. On simple graphics with flat color or hard edges, the gap narrows and WebP can pull even or ahead. The win is largest on photographs — exactly the assets that dominate page weight on most modern sites. AVIF browser support is now above 93 percent globally (Chrome 85+, Firefox 93+, Safari 16+), so the fallback case has shrunk to a small minority.

Does WebP to AVIF preserve transparency?

Yes. WebP supports an alpha channel and so does AVIF, and the pipeline carries it through unchanged. A WebP with a transparent background converts to an AVIF with the same transparent background — no white fill, no color shift, no edge halo, no premultiplied-alpha surprises. This is the opposite of PNG to JPG conversion, where alpha is destructive because JPG has no transparency. If your source has transparency you want to keep — a logo cut-out, a UI sprite, a sticker — AVIF is a safe target and you do not have to flatten beforehand.

Quality and encoding speed

Both formats are lossy here — the encoder runs at quality 85, which is visually near-lossless for photographs (PSNR around 42 dB on real photo input). You cannot get a lossless AVIF from a lossy WebP. The cost of AVIF's compression is encoding speed: a 2-megapixel photo finishes in under a second on Chrome, but an 8-megapixel photo takes around three seconds, and a 24-megapixel photo can take 10 to 30 seconds. Firefox is roughly four times slower than Chrome on AVIF — large images on Firefox can stall the tab for half a minute.

Your privacy

The conversion runs in your browser using a WASM build of the AVIF encoder. Nothing is uploaded, nothing is logged, nothing is queued on a server. If you open DevTools and watch the Network panel while you convert, you will see zero outbound image requests after the page load — the only fetch is the encoder module itself, on the first AVIF conversion of the session. The top-ranked converter on this search uploads files to a server and deletes them an hour later — we never receive your file in the first place.

Frequently asked questions

Is AVIF better than WebP?

For photographs, AVIF wins on compression — typically 20 to 30 percent smaller files at the same perceptual quality, per SpeedVitals DSSIM analysis. On graphics with flat color and hard edges, WebP is competitive or sometimes smaller. Both support alpha and animation. If your audience is on modern browsers (Chrome 85+, Firefox 93+, Safari 16+, currently around 93 percent of global users), AVIF is the better default; otherwise keep WebP as a fallback.

Will I lose quality when converting WebP to AVIF?

Yes — some generation loss is unavoidable. Both formats are lossy, so re-encoding a lossy WebP at AVIF quality 85 (PSNR around 42 dB on photos) introduces a second pass of compression. For photographs the result is visually near-lossless. For graphics with hard edges or flat color, expect mild artifacts. A truly lossless AVIF is not possible from a lossy WebP source — the information is already gone.

Does AVIF support transparency (alpha channel)?

Yes. Both WebP and AVIF support alpha channels, and the conversion carries transparency through exactly — no white fill, no color shift, no halo around soft edges. This is different from PNG to JPG conversion, where alpha is destructive because JPG has no transparency at all. If your WebP has a transparent background, your AVIF will too.

How long does WebP to AVIF conversion take?

A few seconds for typical photos. The first conversion in a session loads the AVIF encoder (about one second). After that, a 2-megapixel image takes under a second on Chrome, 8 megapixels takes around three seconds, and 24 megapixels can take 10 to 30 seconds. Firefox is roughly four times slower on AVIF — a 4K image can take 30 seconds. Mobile devices are another 3 to 5 times slower than desktop.

Is it safe to convert here? Does my image get uploaded?

Your file never leaves your browser. The conversion runs entirely on your device using a WASM build of the AVIF encoder — no upload, no server, no data collection. You can verify it with DevTools open: after the page loads, there are zero outbound image requests during conversion. The top-ranked converter on this search explicitly uploads files to a server; we do not.

Can I convert multiple WebP files to AVIF at once?

Not yet — the current version converts one file at a time. Batch conversion is on the roadmap for a later release. In the meantime, you can open the page in multiple browser tabs and convert files in parallel; each tab runs its own encoder instance and they do not block one another.

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