Convert BMP to WebP
Drop a BMP file below and get a WebP 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 WebP?
For the same picture, WebP usually lands well under the size of the BMP original. That matters when you are trimming page weight or squeezing under an upload limit.
WebP 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.
BMP is from 1986 and stores pixels essentially raw; WebP is from 2010 and was built to make web pages lighter. Converting between them is one of the largest single improvements available in this list, and unusually you get to pick whether it stays pixel-perfect or goes for maximum shrinkage.
Before you convert
Lossless WebP is the right default here
BMP files usually come from screenshots, scanners, Paint or old line-of-business software — flat colour, sharp text, technical drawing. That is exactly the content lossless WebP handles best, and it will often reduce the file by well over 90 percent while remaining pixel-identical. There is no reason to accept any loss on that kind of material when lossless already does this well.
Use lossy only if the BMP holds a photograph
Photographic content is where lossless compression struggles and lossy pulls far ahead — a photo stored as BMP will shrink dramatically further with lossy WebP at quality 80 or so, with nothing your eye can find. Applying that same setting to a screenshot full of text, however, will visibly soften every character.
Check where the file is going
Every current browser reads WebP, so for anything destined for a web page this is settled. But BMP files often come from environments that are behind the times — internal tools, older Windows software, printing workflows — and those same environments frequently do not accept WebP either. If the file is going back into a system like that rather than onto a page, PNG is the safer landing spot.
What carries over
- Every pixel, if you choose lossless
- Transparency, if the BMP had it
- Pixel dimensions
What does not
- The overwhelming majority of the file size
- Support in older non-browser software
BMP vs WebP at a glance
| Property | BMP | WebP |
|---|---|---|
| Compression | Lossless | Lossy |
| Transparency | No | Yes |
| Typical file size | 800-1200% of an equivalent JPEG | 65-75% of an equivalent JPEG |
| Compatibility | Supported by all current browsers and most apps | Supported by all current browsers and most apps |
| Usually comes from | Older Windows software and scanners | Websites optimising page weight |
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 WebP lose quality?
WebP 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 WebP file to be a small fraction of the original with no visible difference.
Is WebP safe to use on a website?
Yes. Every current browser supports it, which covers roughly 97% of visitors. The remaining gap is old software rather than old browsers — a few desktop image viewers and older CMS upload forms still refuse it.