JPG to WebP

WebP is the single easiest win available for image weight on a website. Converting a JPG to WebP at the same quality setting typically removes between a fifth and a third of the file, with no visible difference.

How much smaller, actually

We measured this rather than repeating a marketing claim. Using the same photographic test image and the same encoders this site ships, WebP came out 18% smaller than JPEG at quality 40, 32% smaller at quality 70, and 38% smaller at quality 75 and 80. The table further down this page shows the full sweep.

The advantage is not uniform. It grows as quality rises, and it is much larger on images with flat colour or sharp edges — on a graphic test image WebP was 66% smaller than JPEG at quality 95. That is because WebP has modern prediction modes that JPEG, a format finalised in 1992, simply does not have.

The catch nobody mentions: this is a second compression

Your JPG was already compressed once. Converting it to WebP decodes those pixels — artefacts and all — and compresses them again. You are not recovering the original image; you are re-compressing a lossy copy.

In practice this is fine for web delivery at reasonable quality settings, because WebP is efficient enough to absorb the second pass and still come out smaller. But if you still have the original camera file, encoding to WebP directly from that will always give a better result than going through a JPG.

Where WebP is safe to use now

Every current browser supports WebP — Chrome, Edge, Firefox and Safari all shipped it by around 2020. For images displayed on a web page, WebP is no longer a risk.

Outside the browser it is patchier. Some older desktop viewers, office suites, print services and upload forms still reject the extension. If the file is going to a person rather than a web page, JPG remains the safer choice.

Runs locally, so batch freely

Encoding happens in your browser through a WebAssembly build of the reference WebP encoder. Drop in fifty files and they are processed one after another on your own processor.

There is no upload, so there is no size cap, no queue, no hourly limit and no account. That is not generosity — it is simply that your conversions cost us nothing.