About this tool
BMP files from scanners, old games, and legacy Windows apps are huge because they are uncompressed. PNG stores exactly the same pixels at a fraction of the size, and opens on every modern device.
About the formats: BMP is Windows' original uncompressed bitmap format. Files are enormous and it has no transparency support, so it survives mainly in legacy software, scanners, and old game assets. PNG (Portable Network Graphics) is a lossless image format with full transparency support. It is the standard choice for screenshots, logos, icons, and anything with sharp edges or text, but it produces much larger files than JPG or WebP for photographs.
Everything happens inside your browser. Your file is never uploaded to a server: the conversion runs on your own device using WebAssembly, and the result is downloaded straight from memory. Close the tab and nothing is left behind.
How to use it
- Drop your BMP files into the box above, or click to browse. Nothing is uploaded.
- Click Convert to PNG and wait a moment.
- Download the results individually or all at once as a ZIP.
Frequently asked questions
Is BMP to PNG lossless?
Completely. PNG compression is lossless, so the image is pixel-for-pixel identical.
How much smaller will the PNG be?
Typically 50-90% smaller, depending on how much flat color the image contains.
Is this really free?
Yes. The site is supported by ads, and there are no limits on how many files you convert.
Are my files uploaded anywhere?
No. The converter runs entirely in your browser. Files stay on your device, which also makes it faster than upload-based converters for anything larger than a few megabytes.
Is there a file size limit?
The only limit is your device's memory. Images and audio of any normal size are fine; for video, files under about 500 MB work well on most laptops and phones.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox, and Safari on desktop and mobile. Very old browsers without WebAssembly support will not work.