Convert BMP to PNG
BMP files are usually stored with no compression at all — every pixel written out raw, which is why a simple screenshot can weigh several megabytes. PNG stores the identical pixels losslessly at 50–90% less. This is the rare conversion with no tradeoff: same image, exactly, in a fraction of the space.
Also useful: Convert BMP to JPG
How it works
Drop the bitmaps in — even multi-megabyte scanner output is fine, since your machine does the work locally.
Nothing to configure: PNG re-packs the same pixels losslessly, typically 50–90% smaller than the raw BMP.
Download each shrunken PNG alone, or all of them together as one zip.
BMP vs PNG
Rare in format debates: a verdict with no asterisk. PNG holds the same pixels as BMP, bit for bit, at half to a tenth of the disk — and adds alpha transparency and browser support on top. The only place BMP belongs today is inside software too old to know better.
| BMP | PNG | |
|---|---|---|
| Compression | Usually none (raw pixels) | Lossless |
| Transparency | No | Yes (full alpha) |
| Animation | No | No |
| Support | Universal on desktop | Universal — every browser, editor and OS |
| Best for | Legacy Windows software, raw pixel exchange | Logos, screenshots, graphics with transparency |
Frequently asked questions
No — that is the whole reason I built this. The conversion runs in your browser using WebAssembly, so your files never leave your device; there is no server in the loop at all. It also means the tool keeps working offline once the page has loaded, and there is no file size limit beyond your device’s memory.
Completely. BMP stores raw pixels and PNG compresses those same pixels with a lossless algorithm — the decoded result is bit-for-bit identical. It is the closest thing to free disk space you will find in image formats.
Because most BMPs skip compression entirely: a 1920×1080 screenshot is 1920 × 1080 × 3 bytes — about 6 MB — no matter how simple the content. The format dates from early Windows, when decoding speed mattered more than disk space.
Legacy Windows software, MS Paint defaults, scanner utilities, medical and industrial equipment, and game modding tools. If a program was written before 2005, odds are it speaks BMP.
Only the bytes. Both store exact pixels; BMP writes them raw while PNG runs them through DEFLATE compression, which is why the same screenshot drops 50–90% with nothing changed. PNG also adds what BMP never had: an alpha channel, gamma metadata, and first-class support in every browser. BMP’s one edge — trivially simple decoding — stopped mattering when computers left the 1990s.
A few, and they are all legacy: game modding pipelines that parse BMP headers directly, industrial and medical equipment with fixed import lists, and ancient Windows tools that predate PNG support. If your file is destined for one of those, keep the BMP alongside the PNG. Everything else — email, web, documents, editors — reads PNG happily, at a fraction of the disk space.
Related tools
Convert BMP to JPG
Convert BMP to JPG in your browser — free, private, no upload or signup. Giant uncompressed bitmaps become shareable photos, typically 95–98% smaller.
Convert BMP to WebP
Convert BMP to WebP in your browser — free and private, nothing uploaded. Jump a legacy bitmap straight to the modern web format — savings north of 95%.
Convert PNG to WebP
Convert PNG to WebP in your browser — free, no upload, no signup. Keeps alpha transparency, cuts file size by 60–90%, and shows the exact savings per file.
Convert BMP to PDF
Convert BMP to PDF in your browser — free, no upload, no watermark. Old scans and bitmaps become compact, sendable PDFs — often far smaller, losing nothing.