Convert BMP to PNG
To convert BMP to PNG, drop the .bmp file into the converter on this page and click the button; the PNG downloads seconds later. Because BMP stores pixels raw and PNG is lossless, the result is a pixel-for-pixel copy at a fraction of the size, produced entirely on your own device.
Drop your BMP here
It becomes a PNG right in your browser, up to 100 MB
Your file never leaves your device
Why convert BMP to PNG?
BMP files come out of legacy Windows tools, scanner software, lab equipment and decades-old archives, and they are huge: typically three bytes per pixel with no compression whatsoever. PNG stores the identical pixels losslessly at a fraction of the weight, displays in every browser, and is accepted by effectively every modern app and upload form, none of which is true of BMP. This is the rare conversion with no downside: nothing is traded away, the file just stops being enormous and awkward. Our automated gate verifies the decode is pixel-exact across a corpus of BMP variants, including odd widths where the format's row padding trips careless decoders.
What is BMP?
BMP is the Windows bitmap format from 1987: pixels stored essentially raw, usually with no compression at all. Ancient tooling, scanners, screenshots from legacy systems and some scientific software still emit it, and almost everything can read it, but the files are enormous for what they contain. Converting a BMP loses nothing, because there was never any lossy compression inside to begin with.
What is PNG?
PNG (Portable Network Graphics) is a lossless image format from 1996. It compresses with DEFLATE, keeps every pixel exactly as authored, and supports a full 8-bit alpha channel for transparency. That makes it the default choice for screenshots, UI mockups, logos and anything with sharp edges or text. The tradeoff is size: photographs stored as PNG are often several times larger than a visually identical lossy file.
Quality and what to expect
This conversion is exactly lossless in the strict sense: the decoded BMP pixels and the PNG pixels are identical, byte for byte per channel, and our release tests assert that on real fixtures. Standard 24-bit bitmaps, the kind virtually all BMP files are, convert perfectly; exotic variants (RLE-compressed, 16-color, or alpha-carrying BMPs) are rarer and decode through the browser's own bitmap engine. Size typically drops by 50-90% depending on content. BMP carries no EXIF-style metadata block, so there is nothing to strip or leak.
BMP to PNG FAQ
Is anything lost converting BMP to PNG?
No. BMP is uncompressed and PNG is lossless, so the pixels in the output are identical to the pixels in the input. This is verified automatically: our test suite decodes both sides and compares every pixel value.
How much smaller will the PNG be?
Screenshots and graphics often shrink by 80-90% because flat regions compress superbly. Noisy photographic content shrinks less, but PNG essentially never comes out larger than the raw bitmap it came from.
Why do BMP files even exist anymore?
Inertia and simplicity. The format is trivial to write, so embedded systems, scanners, scientific instruments and old Windows software keep producing it. It was never designed for sharing or the web, which is where PNG takes over.
Does the bitmap get uploaded for conversion?
No. The file is decoded by your browser on your machine and re-encoded to PNG by WebAssembly in a web worker. Watch the network tab while converting: no request carries the image.