Media Tool · 100% Client-Side

WebP Image Converter

Convert PNG, JPEG, and other raster images to the WebP format entirely in your browser. The image is redrawn on an off-screen canvas and encoded locally — nothing is ever uploaded to a server.

Note: animated GIFs are flattened to their first frame, since the converter encodes a single static WebP image.

How the WebP Converter works

How it works

The converter reads the selected file through the File API and turns it into an object URL, which is decoded into an in-memory HTMLImageElement. That image is then drawn at its natural dimensions onto an off-screen 2D canvas with drawImage, and the canvas is re-encoded as WebP with toBlob('image/webp', quality). The quality slider (0 to 1) maps directly to the WebP encoder: lower values produce smaller files with more visible artifacts, higher values preserve more detail. WebP is a modern raster format that supports both lossy and lossless compression, and the canvas encoder keeps the alpha channel intact, so transparent sources stay transparent. Because every step runs inside the browser, the source image never leaves your device.

Use cases

Front-end developers use this to cut page weight by converting PNG and JPEG screenshots or photos to WebP before uploading to a CMS or CDN. Designers use it to produce smaller assets that still keep an alpha channel, and it is a quick single-file conversion when you want to avoid sending images to an online service.

Troubleshooting

If you see a "canvas returned no data" error, the browser cannot encode WebP — switch to a recent version of Chrome, Edge, Firefox, or Safari. Animated GIFs are flattened to their first frame because the converter emits a single static WebP image. If the output is larger than the source, the original is probably already well optimized; lower the quality or start from an uncompressed export. Transparency is preserved, but a source without an alpha channel will simply stay opaque.

FAQ

Is my image uploaded to a server during conversion?
No. The file is decoded and re-encoded locally on your device using the Canvas API, and no data is ever sent over the network.
Does WebP support transparency?
Yes. WebP carries an alpha channel, so transparent PNGs and GIFs keep their transparency in the output.
Can it convert animated GIFs or animated WebP files?
No. The converter produces a single static WebP image, so animated GIFs are flattened to their first frame.
Why is my WebP file larger than the original?
WebP is not always smaller, especially for sources that are already heavily optimized. Try lowering the quality slider or starting from an uncompressed original.
Which browsers can produce WebP files?
Recent versions of Chrome, Edge, Firefox, and Safari all support WebP encoding through the Canvas API. Older browsers may return no data, in which case an error message is shown.