PNG to WebP converter

This is a conversion made for the web. WebP holds everything PNG can — full transparency, sharp edges, flat colour — and stores it far more efficiently. For site assets, app icons and any graphic that has to load over a network, it is close to a free win: the same picture, typically a third of the size, with transparency intact. The only real question is whether whatever consumes the file understands the format.

When you actually need this conversion

• You are optimising images for a website and the PNGs are the heaviest thing on the page.
• You have a logo or icon with a transparent background that needs to be smaller without becoming a JPEG-with-a-white-box.
• You are building a set of app or extension assets where every kilobyte counts and the target platform is a browser.

What to watch out for

• In lossy mode WebP is an approximation. For a photograph that is fine; for a diagram with fine lines and text, use lossless WebP or leave it as PNG.
• Older software may not open the result. This is a format for the web, not for handing to a print shop or a colleague's 2018 desktop application.
• Very small icons sometimes come out larger as WebP — the container overhead stops being negligible below about 100×100 pixels.

PNG and WebP, side by side

For screenshots and interface graphics, lossless WebP typically comes out 20–30% smaller than PNG with identical pixels. For photographs saved as PNG, switching to lossy WebP can cut the size by 90% with no visible change.

How the conversion works here

Your file is decoded in a Web Worker inside this browser tab — by the browser's own image pipeline where it can, and by a WebAssembly build of libheif or libavif where it cannot. The decoded pixels are then re-encoded with Google's libwebp, the same encoder Squoosh uses.

All of that happens on the processor in front of you. There is no upload step, no queue and no server, which is why there is no size cap, no daily allowance and no paid tier — and why the whole thing keeps working with the network switched off.

Doing more than one thing

Most people converting a format also need it smaller or a different size. The result screen hands your converted files straight to the compressor or the resizer in one click — no second download, no re-selecting files. If you need several formats, the general converter lets you pick the output each time.