Images are converted on your device. Nothing is uploaded.
How to compress a BMP file
Drop your BMP files into the tool and pick a format to save them as. Each image is converted right away, and the preview shows the original and compressed versions side by side so you can drag the divider and check quality. Change any setting and the files update on their own. Download one at a time, or get the whole batch as a ZIP.
Why BMP files are so big
Most BMP files store every pixel raw, with no compression at all. A 1920 × 1080 screenshot saved as a 24-bit BMP is about 6 MB no matter what's in it. The same image as a JPG is often a few hundred kilobytes, and as a PNG it can be smaller still if it's mostly flat color. That's why converting a BMP usually cuts the size by 80 to 99 percent.
Which format should you choose?
| Format | Best for | Notes |
|---|---|---|
| JPG | Photos and scanned documents | Opens everywhere. Lossy, with no transparency. |
| WebP | Websites | Usually smaller than JPG at the same quality, and supports transparency. |
| PNG | Screenshots, diagrams, logos | Lossless. Every pixel stays exactly the same. |
| PNG, 256 colors | Screenshots, icons, simple graphics | Often much smaller than a regular PNG. Images with 256 colors or fewer stay pixel-perfect. |
| BMP, 256 colors | Software that only accepts BMP | Stays a BMP, but 8-bit with optional RLE compression, so it's far smaller than a 24-bit BMP. |
When you need to keep the BMP format
Some older programs, embedded displays, label printers and game engines only accept BMP. For those, choose BMP, 256 colors. The tool reduces the image to a 256-color palette and saves an 8-bit BMP, which is about a third the size of a 24-bit BMP before any other savings. RLE compression shrinks it further for images with large areas of flat color. If your software won't open the result, turn RLE off, since a few programs don't support it.
Frequently asked questions
Can I compress a BMP without losing quality?
Yes. Choose PNG and the image stays pixel-for-pixel identical while the file gets much smaller. PNG, 256 colors is also lossless for images that have 256 or fewer colors to begin with.
What quality should I use for JPG?
Around 80 to 85 looks nearly identical to the original for most photos. Go lower for thumbnails, or higher for images with fine text. Resizing large images usually saves more than lowering quality.
What does dithering do?
When an image is reduced to 256 colors, dithering blends nearby colors in a fine pattern so gradients and photos look smooth instead of banded. Turn it off for flat graphics and screenshots, where it can add unwanted speckles and make the file larger.
Can I compress many BMP files at once?
Yes. Drop in a whole folder's worth. Every file uses the same settings, and Download all saves them as one ZIP.
Are my images uploaded?
No. Everything happens in your browser, and your files never leave your device.