Convert BMP to PNG
Your files are processed on your device. We never upload them.
How to convert BMP to PNG
- 01A ▸Choose your BMP files, or drop them on the page.
- 02A ▸Select Convert to PNG.
- 03A ▸Download each PNG, or all of them as a zip.
About BMP to PNG
Where BMP files come from
BMP files come from Windows Paint, screenshot tools, older scanners, and legacy and industrial software. They are uncompressed and many websites reject them. PNG keeps the same exact pixels in a smaller file that every app and site accepts.
What changes
- Every pixel is kept exactly; PNG compression is lossless.
- The file gets smaller, a lot for flat graphics and less for photos.
- Transparency in 32-bit BMPs is kept.
- Palette (8-bit and lower) bitmaps become full-colour PNGs with the same colours.
Measured
Our 12-megapixel sample photo (4032 by 3024) saved as a 24-bit BMP, converted in Chrome on a laptop. Photos are the hardest case for PNG; screenshots shrink much more. Phone timings are still to be measured.
| BMP file | 35 MB |
|---|---|
| PNG file | 20 MB |
| Time in Chrome (laptop) | 0.9 seconds |
In your browser
Every current browser reads BMP and writes PNG itself, so nothing extra is downloaded.
Limits
- Photos stay large as PNG; JPG is far smaller for them.
- Very large bitmaps may be reduced to about 16 megapixels on iPhones. The result says so.
- Rare compressed and OS/2 bitmaps may not open; the result says so for that file.
Other options
- BMP to JPG: a much smaller file for photos.
- Compress image: shrink the PNG further by reducing its colours.
- Image to PDF on Open PDF Toolkit: put the images into a PDF.
Questions
Is BMP to PNG lossless?
Yes. PNG compresses without loss, so every pixel is exactly the same as in the BMP. Our tests compare the pixels.
Are my images uploaded?
No. Your files are processed on your device. We never upload them.
How much smaller is the PNG?
It depends on the picture. Screenshots and drawings with flat colour often shrink by 90 percent or more. Photos shrink less; our 35 MB sample photo became a 20 MB PNG.
Does it keep transparency?
Yes. If a 32-bit BMP has transparency, the PNG keeps it.
Should I choose PNG or JPG?
PNG for screenshots, diagrams, icons, and anything with text. JPG for photos, where it is many times smaller.