Technical and design
Image to WebP and AVIF Converter
Convert images to WebP or AVIF in your browser, set the quality, and see how much each file shrinks.
Runs in your browser; nothing is uploaded. · Free, no account · 3 min
The files stay in this browser tab. Nothing is uploaded.
Each encoder scales quality its own way, so 80 in WebP and 80 in AVIF are not the same picture.
Importing a saved run into your account is coming soon. Until then, your last runs stay in this browser only, and you can download your files.
How to use
- Choose up to 20 image files.
- Pick WebP or AVIF, set the quality, and set a longest-side limit if you want to resize.
- Run the conversion and compare each file's size before and after.
- Download each file, or all of them as a zip.
What it checks and how it works
The tool decodes each picture with the browser, resizes it if you set a limit, and encodes it with jSquash, which packages the WebAssembly codecs from Squoosh: libwebp for WebP, which Google documents, and libavif for AVIF, the AV1 Image File Format specified by the Alliance for Open Media. Quality runs from 1 to 100, and each encoder scales it in its own way, so 80 in WebP and 80 in AVIF do not give the same picture. A lossless WebP option is available. The work happens on your device, and nothing is uploaded.
Limits: up to 20 files, each up to 25 MB and 40 million pixels. The picture is drawn on a canvas and re-encoded, so camera metadata (EXIF), color profiles and all but one frame of an animation are not kept. AVIF encoding is slow for large images. A file that is already well compressed can grow when re-encoded, and the tool warns you when a result is not smaller. The encoders could not be run in a browser while this tool was written, so test a few of your own files before relying on it.
Sources
- Google for Developers: WebP, an image format for the web opened 29 Oct 2026
- Alliance for Open Media: AV1 Image File Format (AVIF) specification opened 29 Oct 2026
- jSquash (npm packages, Apache-2.0): WebAssembly image codecs from Squoosh opened 29 Oct 2026
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Questions
About this tool
No. The picture is decoded and encoded in your browser tab with WebAssembly, and nothing is sent anywhere.
WebP is documented by Google and AVIF is specified by the Alliance for Open Media; compare the size and look of your own files at a few quality settings, because results depend on the picture.
A file that is already compressed well can grow when it is re-encoded at a high quality. Lower the quality or keep the original.
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