Image Tools
BMP to PNG Converter
Legacy bitmaps to modern lossless PNG — often 5–10× smaller with identical pixels.
In short
Convert BMP to PNG online: legacy bitmaps re-encoded as compact, lossless PNG — batch conversion in your browser with nothing uploaded.
By NaveenKumar T · Updated
- Batch conversion
- Lossless conversion
- Often 5–10× smaller
Runs entirely in your browser — nothing you paste or open here is uploaded, logged, or stored.How we handle data →
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Converting BMP to PNG, explained
BMP files are typically uncompressed — every pixel stored raw, which is why a screenshot can weigh megabytes. PNG stores the identical pixels losslessly but compressed: converting is pure win, with files often shrinking 5–10× and not one pixel changing. The conversion runs through your browser's native decoders, so it's instant even for large bitmaps.
Common sources: old Windows tools, MS Paint exports, industrial and scientific software. Convert once and the files become web-friendly, email-friendly, and version-control-friendly.
Cleaning out a BMP backlog
BMPs tend to arrive in herds: a folder of instrument screenshots from lab equipment, years of MS Paint annotations, exports from an industrial HMI, sprite sheets from retro game tooling. Because the conversion is lossless and the size win is enormous, batch-converting an entire archive is risk-free housekeeping — drop the lot, convert, Save all, reclaim the disk. A 40 MB folder of bitmaps routinely lands under 6 MB as PNGs with every pixel intact. Conversion runs through the browser's native BMP decoder onto a canvas, so even a 20 MB bitmap converts in well under a second, and 1-bit, 4-bit, 8-bit palette and 16/24/32-bit files all decode without any extra library.
If the images are photographs rather than UI captures or line art, consider PNG to JPG or PNG to WebP as a second hop — photographic content compresses far better lossily, and the chain stays honest because the first hop lost nothing. One detail about the pixels: the canvas always writes 8-bit-per-channel RGBA, so a 16-color or 256-color palette BMP becomes a truecolor PNG — still far smaller than the bitmap, but not as small as a palette PNG could be. Running the results through the PNG Compressor reduces them back to palette form losslessly. Output names keep the base name with a .png extension, and since BMP stores no color profile or metadata, nothing is lost on that front either.
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Frequently asked questions
Everything you need to know about the BMP to PNG.
01Which BMP variants decode?
1-, 4- and 8-bit palette bitmaps and 16-, 24- and 32-bit files all decode through the browser's native BMP decoder — no extra library, and a 20 MB bitmap converts in well under a second. The canvas writes 8-bit-per-channel RGBA, so a 256-colour BMP becomes a truecolor PNG; run it through the PNG Compressor to reduce it back to palette form losslessly.
02Is BMP to PNG really lossless?
Completely — both formats store exact pixels; PNG just compresses them losslessly (think ZIP for images). The decoded output is bit-identical imagery at a fraction of the size.
03How much smaller will the PNG be?
It depends entirely on content, because PNG compression is lossless. Screenshots, dialogs, charts and line art with large flat areas routinely shrink 5–20×: a 6 MB 1920×1080 bitmap becomes a few hundred kilobytes. Photographs stored as BMP only lose 30–50%, since sensor noise doesn't compress losslessly — convert those on to JPG or WebP afterwards. Most BMPs are opaque 24-bit, so the PNG comes out opaque too; a real alpha channel survives only when the BMP used a header that declares one.
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