The best free route is a browser-based converter that re-encodes your JPG or PNG to WebP at a quality you choose and shows the before and after file sizes, all on your own device. There is no account, no batch limit metered by a server, and the images are never uploaded.
Free image to WebP converter. Turn JPG or PNG photos into WebP at a quality you choose, compare file sizes, and download. All in your browser.
Open Image to WebP Converter → Free toolFree online image format converter. Change a picture between PNG, JPG and WebP right in your browser and download the converted file. Private.
Open Image Format Converter →WebP typically stores the same photo in a noticeably smaller file than an equivalent JPEG, and it supports transparency like PNG, which makes it a strong default for websites where image weight drives load time. All current major browsers can display WebP, so for web use the old compatibility worry is largely gone.
Three things: control, feedback and privacy. You want to choose the quality level rather than accept a fixed setting, see the resulting file size next to the original so you can judge the trade, and avoid pushing your image library through someone's server to do it. A client-side converter checks all three boxes, and a companion format converter handles the reverse trips between PNG, JPG and WebP when you need them.
All current major browsers support WebP. Only very old browser versions lack it.
Yes. You pick the quality level and can compare the original and converted file sizes before downloading.
No. The conversion runs in your browser, so your pictures never leave your device.