PNG to WebP Converter

This tool converts PNG images to WebP in your browser. People usually do it for one reason: WebP makes the same picture noticeably smaller, so pages load faster and screenshots, product shots and site assets take up far less space. WebP is supported by every current browser — Chrome, Edge, Firefox and Safari — and by most software released since about 2020.

The saving comes from how the two formats compress. PNG is lossless: it stores every pixel exactly, which is ideal for screenshots, diagrams and logos with flat colour and sharp text, but expensive for photographs. WebP can be lossless or lossy, and the encoder the browser gives this tool writes lossy WebP at the quality you choose — 90 out of 100 by default, where the loss is generally hard to see. There is no lossless-WebP option through the browser's canvas, so the PNG's exact bytes are not preserved and soft or semi-transparent edges can shift very slightly. If you need the pixels bit-for-bit, keep the PNG.

Unlike converting to JPG, transparency is kept. WebP has an alpha channel just like PNG, so see-through and semi-transparent pixels stay transparent — no background colour is filled in. That makes WebP the right small-file target for a cut-out logo or a product shot on a transparent background.

On size, be honest with yourself: WebP is smaller than PNG in most photographic cases, often dramatically, but not always. A tiny image or a flat-colour icon that PNG already compresses well can occasionally come out slightly larger, because it is being re-encoded lossily at a fixed quality. The results list shows each file's size before and after and reports a larger file as larger — a positive percentage — rather than hiding it, so you can keep the PNG in that case.

The one real catch is compatibility. Very old software cannot open WebP: older Office versions, some pre-2020 Windows photo viewers, a few CMSs and print workflows, and image editors that predate it. If something rejects the file, convert to JPG instead, or keep the PNG. Nothing leaves your device — the images are read into your browser's memory, converted there and offered back as downloads, which you can confirm in the Network tab of your browser's developer tools. Up to 50 files per batch, each up to 50 MB, downloadable individually or as a ZIP.

1. Each file's first eight bytes are checked for the PNG signature (89 50 4E 47 0D 0A 1A 0A). Anything else is rejected with a message naming what the file really is. 2. The chunks before the image data are scanned for an acTL chunk; if one is present the PNG is animated and you are told only the first frame is kept. 3. Quality (1–100) is validated and converted to the 0–1 scale the browser's encoder takes. No background colour is used, because WebP keeps the alpha channel. 4. The browser decodes the PNG at full size and draws it onto a canvas of the same dimensions, alpha included — nothing is flattened. 5. The canvas is encoded with canvas.toBlob("image/webp", quality) — lossy WebP — and the file is named after the original with a .webp extension. Sizes before and after are shown per file.