BMP is Windows' basic bitmap that stores pixels as they are, without compression. BMP opens in most environments, but another format such as WebP may suit some uses better.
WebP is a web format that is smaller than JPG and supports transparency and animation. When you convert BMP to WebP, the file gets smaller and you get a format that supports transparency. See the comparison below for what changes.
This converter reads the file itself to confirm it is BMP, then converts it to WebP right in your browser. Your image is never uploaded.
BMP vs WebP: what's the difference?
| Item | BMP | WebP |
|---|---|---|
| Compression | None (uncompressed) | Lossy or lossless |
| Transparent background | No | Yes |
| Animation | No | Yes |
| Introduced | 1990 | 2010 |
| Support in programs and upload forms | broad | moderate |
| Shown directly in browsers | Yes | Yes |
| Photo file size (JPG = 1) | about 12× | about 0.7× |
What is BMP?
BMP is a bitmap format from Windows that mostly stores pixel values as they are, without compression. Its simple structure makes it easy for programs to read, but the files are so large that it is rarely used on the web.
What is WebP?
WebP is a web image format Google released in 2010. At the same quality it can be roughly 25-35% smaller than JPG, and it handles lossy and lossless compression, transparency and animation in a single format.
What changes when you convert BMP to WebP
Converting doesn't add a transparent background
BMP has no transparency information, so converting to WebP keeps the background as it is. To remove a background you need a separate background-removal tool.
Lossy compression is applied
BMP loses no quality, but WebP drops information the eye barely notices to shrink the file. Even next to the BMP original, the default quality of 90 is hard to tell apart, and the slider lets you tune size against quality.
You can adjust quality, size and background color
When converting BMP to WebP, you can use the quality slider (default 90), exact width-and-height sizing with margin fill, and percentage resizing. BMP is lossless, so lowering quality to around 80 usually still looks natural. Lower it when size matters, and raise it to 95 or more for archiving.
How the file size changes
WebP is far smaller than BMP (roughly 1/17 the size). This is for photos; for simple images such as logos and screenshots, PNG can actually come out smaller.
WebP has narrower support than BMP
BMP support is broad and WebP support is moderate. Check that the recipient can open WebP first, and if you're not sure, JPG or PNG is safer.
When to convert
- You need to shrink a BMP file for an email attachment or an upload size limit
- You want to make BMP images lighter so pages load faster
- You're preparing an image for typical WebP uses (optimizing website images, transparent web graphics)