Convert JPG to WebP

The saving is usually large

WebP generally produces a file noticeably smaller than the equivalent JPG at a quality nobody can distinguish on screen. For a typical photograph that often means half the size or less, and the saving grows as you lower the quality while the image still looks right. For a page with many images, that compounds into a much faster load, which is the whole point of the format on the web.

NoteIndicative figures for a typical image at comparable visual quality. Exact results depend on content, encoder, and quality setting.

WebP adds something JPG cannot do

Beyond size, WebP supports a real alpha channel with smooth partial transparency, where JPG can only be fully transparent or fully opaque. That makes it a better output for a logo or an icon on a transparent background, and it avoids the white box that a transparent PNG placed on a dark page produces. If transparency matters, WebP is strictly better than JPG here, and better than a PNG that is several times the size.

• WebP supports smooth transparency, JPG does not.
• That makes it a good output for logos and icons on a transparent background.
• A transparent JPG needs a fill colour and shows a rectangle on a dark page.
• For images with no transparency, the advantage is size alone.

Compatibility, and the honest caveat

WebP is supported across all current major browsers and has been for years, so treating it as an experimental format is out of date. The remaining caveats are older browsers, some in-app webviews, and a handful of older design, email, and publishing tools that will not accept it. For a website aimed at a general audience it is a safe default. For email, or for a file going into a system you do not control, JPG remains the safer choice.

• WebP is safe for a general website audience today.
• Some email clients still render it poorly or not at all.
• Older design and publishing tools may reject it on upload.
• When in doubt about the destination, use JPG.

MDN: image file type and format guide

One conversion, and keeping the original

Both formats are lossy, so converting from a JPG re-encodes an already reconstructed image and discards a little more. One conversion is entirely normal and is what every website does. What is not sensible is converting repeatedly, or keeping a chain of intermediates. Convert from the original each time, keep the original, and if you need a smaller file than WebP can give, consider AVIF rather than lowering the quality further.

• One conversion from JPG to WebP is a normal, expected operation.
• Each further conversion discards a little more, so avoid a chain.
• Keep the original JPG as your master.
• For smaller files at the same quality, try AVIF rather than a lower WebP setting.