Convert BMP to JPEG XL
Drop a BMP file below and get a JPEG XL back. The conversion happens on your own machine, so nothing is uploaded and there is no size or quantity limit beyond what your browser can hold in memory.
Drop images here
Ctrl/⌘ VPaste a screenshot or copied image
Accepts BMP
Lower means a smaller file. 75 is a good default for photos.
100% in your browser Files are never uploaded.
Why convert BMP to JPEG XL?
For the same picture, JPEG XL usually lands well under the size of the BMP original. That matters when you are trimming page weight or squeezing under an upload limit.
JPEG XL supports an alpha channel, so you can cut out a background after converting. The conversion itself will not invent transparency that the BMP file never had.
Of all the destinations for an old BMP, this is the one that makes the most sense for long-term storage. Both formats are lossless, so the picture does not change at all — but BMP spends three bytes per pixel regardless of content, while JPEG XL's lossless mode is among the most efficient ever built. You keep everything and pay a small fraction of the storage.
Before you convert
Lossless on both ends means nothing to decide
No quality slider, no artefacts, no one-way door. Every pixel arrives exactly as it left and can be converted back at any point without loss. For archiving material from scanners, instruments or legacy software — which is where most BMP files come from — this removes the usual anxiety about compressing an irreplaceable original.
It is a storage format, not a delivery format
As of August 2026, only Safari opens a JXL without the user enabling something; Chrome 145 has a decoder behind a flag with default-on expected in the second half of the year. If anyone other than you needs to open these files in the near term, PNG is the safe lossless choice and WebP is the efficient one. JXL is for the copy that sits on a disk.
Ask whether you need lossless at all
Losslessness is worth paying for when the image is a master that will be edited, or a record that must not drift. If the BMP is simply a screenshot you want to keep or send, a lossy format will be far smaller with no visible difference, and the archival argument does not really apply.
What carries over
- Every pixel, exactly
- The ability to convert back unchanged
- An open format with no licensing questions
What does not
- The overwhelming majority of the file size
- Practical viewability, for now
BMP vs JPEG XL at a glance
| Property | BMP | JPEG XL |
|---|---|---|
| Compression | Lossless | Lossy |
| Transparency | No | Yes |
| Typical file size | 800-1200% of an equivalent JPEG | 45-60% of an equivalent JPEG |
| Compatibility | Supported by all current browsers and most apps | Safari and recent Chrome; still uncommon elsewhere |
| Usually comes from | Older Windows software and scanners | Long-term archives and photography workflows |
Frequently asked questions
Are my BMP files uploaded anywhere?
No. The decoder and encoder are WebAssembly modules that run inside this page. The network tab may show a codec downloading the first time you use a format, but no request contains your file. On supported browsers, a codec that has already been used is cached so the same conversion can work offline.
Is there a file size or quantity limit?
There is no limit imposed by us. The practical ceiling is your device’s memory, since the image has to be held uncompressed while converting. On a typical laptop, images up to around 100 megapixels convert without trouble.
Will converting to JPEG XL lose quality?
JPEG XL is a lossy format, so some data is discarded. At the default quality setting the difference is not visible at normal viewing sizes. If you need an exact copy of the pixels, choose PNG instead.
Does it work on a phone?
Yes. The same WebAssembly modules run on mobile browsers. Conversion is slower than on a desktop because phone CPUs are weaker, and very large images are more likely to hit memory limits.
Why is my BMP file so large?
BMP stores pixels essentially uncompressed, so a single photograph can run to tens of megabytes. That alone usually makes the conversion worthwhile — expect the JPEG XL file to be a small fraction of the original with no visible difference.
Is JPEG XL ready to use?
Partly. Safari has supported it for some time and Chrome shipped stable support in early 2026, but overall coverage still sits around 15%. It is a sound choice for archiving, where compression quality matters more than universal support, and a poor one for images going onto a public website today.