JPG to JPEG XL
Nothing you choose here leaves your browser. There is no server to send it to — the conversion happens on your own device, using the codecs your browser already has, and nothing is uploaded, stored or seen by anyone.
What this conversion costs you
The format JPEG XL was built to replace, converted by it. JPEG XL typically saves 20-30% over JPEG at the same quality. It can also repack an existing JPEG losslessly, which this page does not do — this is the ordinary conversion, which decodes and re-encodes. No browser writes JPEG XL, so an encoder is fetched when you ask.
Some detail, permanently. JPEG XL is lossy. The quality setting decides how much goes, and it cannot be put back by converting again.
The metadata. Going through a canvas drops EXIF, so the camera, the date and any GPS coordinates do not survive. That is a side effect rather than a feature, and a useful one.
How it works, and why nothing is uploaded
Your browser can already read JPG. No browser writes JPEG XL — and almost none reads it either — so this page offers to fetch an encoder. It is 440 KB, served from this site rather than anybody else's, fetched only if you ask and only once, and kept in your browser's ordinary cache. Nothing is installed and your picture is still never sent anywhere.
It also means the page can tell you when your browser cannot do it, which it will say plainly rather than producing a broken file. The one thing it will never do is hand you a file with the wrong contents: browsers quietly return a PNG when asked for a format they cannot write, so every conversion here checks what came back and refuses if it is not what was asked for.
Where to go next
The same conversion, the other way round, and the other targets:
- JPEG XL to JPG — the same conversion the other way
- JPG to PNG — lossless, with real transparency, and the safe choice for anything with text or sharp edges
- JPG to WebP — Google's format, usually a good deal smaller than JPG or PNG at the same quality
- HEIC converter — iPhone photographs, which need a different approach
What this does not do
It converts one picture at a time from each file, and does not edit, crop or retouch. It cannot convert a format your browser cannot read — JPEG XL, QOI and HEIC all need something extra, and HEIC has a page of its own.
It does not upload anything, so it cannot work on a file that is not on the device you are using. And it does not preserve metadata: if you need the EXIF kept, this is the wrong tool, and if you wanted it gone, this is a convenient way to do it.