JXL to WebP Converter

WebP is a better destination than JPG here

JXL and WebP are both modern, efficient formats, so converting between them loses little compared with converting to JPG. WebP is supported across all current browsers, so it solves the same compatibility problem that motivates most JXL conversions, and it is substantially more efficient than JPG. The one caveat is that it remains lossy in its default mode, so a quality setting is still needed unless lossless is chosen.

MDN: image file type and format guide

Lossless WebP is available and often the right answer

Because WebP has a lossless mode, a JXL can be converted without discarding anything at all, which is not true of a JPG conversion. Lossless WebP is usually smaller than PNG for the same pixels, so it gives an exact copy at a reasonable file size, and it opens in every current browser. The trade is that older desktop software may not support it, and an email client is still better served by JPG. For web delivery, a lossless WebP is usually a better answer than either of those.

• Lossless WebP keeps every pixel and is smaller than PNG.
• It opens in all current browsers.
• Older desktop software may not support it. Use PNG or JPG there.
• Email is still better served by JPG.

Two lossy formats means a second generation of loss

If the JXL source was lossy, converting to WebP in its default mode encodes the image a second time, and the artefacts compound. If the source was lossless, this is the first lossy step, which is much more comfortable. The practical advice is to use lossless WebP whenever the pixels matter, which sidesteps the question entirely, and to use lossy WebP only when the file is for the web at a size where the difference is invisible. Keep the JXL as the master in both cases.

• A lossy JXL to lossy WebP is a second generation of loss.
• A lossless JXL to lossy WebP is the first, which is safer.
• Use lossless WebP when the pixels matter. It sidesteps the issue.
• Keep the JXL as the master either way.

Why the file usually gets smaller

JXL compresses more efficiently than WebP, so a lossy to lossy conversion will usually produce a larger file than the JXL it came from. That is the opposite of most conversions on this site and it is worth stating plainly rather than discovering later. The cases where WebP is smaller are a JXL that was saved at a very high quality, where a moderate WebP setting produces a comparable image more efficiently, or a JXL saved losslessly, where lossy WebP is dramatically smaller. If a larger file is acceptable for the compatibility gain, that is a reasonable trade; it is just not the usual one.

NoteA lossy JXL to lossy WebP usually grows the file. The compatibility gain has to be worth it.