BMP to PNG Converter
Convert BMP — the old Windows bitmap format — into PNG, lossless, and it keeps transparency. Runs entirely in your browser.
Why convert BMP to PNG?
PNG is what BMP should have been: lossless, so nothing is given up, but actually compressed. For screenshots, interface captures and flat-colour graphics — which is most of what still arrives as a BMP — the file typically shrinks by an order of magnitude while staying pixel-identical.
What changes when BMP becomes PNG
The pixels are unchanged. The whole size reduction comes from compression, and it is largest on flat colour and smallest on photographs. Any transparency a 32-bit BMP carries is preserved.
Why this one is different
Every other BMP to PNG converter uploads your files to their server, which is why they cap file sizes and ask you to sign up. This one does the work on your own machine, so it can afford not to.
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Questions
How do I convert BMP to PNG?
Drop your BMP files onto the box above and each one is converted to PNG straight away. Then download the results, individually or together as a ZIP. There is no upload step and no account.
Is this really lossless?
Yes. Both formats store exact pixel values; PNG simply encodes them more cleverly. You could convert back and forth indefinitely without degrading anything.
How much smaller will it be?
For a screenshot or a diagram, commonly five to twenty times. For a photograph stored as a BMP, closer to two or three — PNG cannot work miracles on photographic detail.
Do my files get uploaded anywhere?
No. Everything happens in this tab. Your files are never sent to a server, which is why this still works if you disconnect from the network after the page has loaded.