BMP to PNG — Convert BMP Bitmaps to PNG in Your Browser
Convert BMP bitmap files to PNG. Massive size reduction, lossless output, runs entirely in your browser. No uploads, no accounts, no limits.
Drop your BMP image here
or click to browse (max 50MB)
BMP is the oldest image format still in regular use. It was the native bitmap format for Windows 3.0 in 1992 and it has barely changed since — same uncompressed pixel grid, same 24-bit default, same lack of any real compression. The reason it is still around is that every version of Windows, every scanner driver, and a few legacy screen-capture tools still emit it. The reason to convert it is that BMP files are 5 to 10 times larger than they need to be for what they show. A 1920 by 1080 screenshot from a Windows tool is 6 MB as a BMP and 400 KB as a PNG, with no visible difference.
The non-obvious thing about the conversion is that it is technically a no-op at the pixel level. BMP and PNG are both lossless formats, so every pixel that comes out is identical to every pixel that went in. The conversion is a rewrap — swapping the BMP container’s uncompressed pixel grid for PNG’s deflate-compressed one. That is why the file size drops by 70 to 90 percent without any visible change. There is no quality slider because there is no quality loss to trade against size.
For a final hand-off: if the BMP came from a Windows screenshot tool (Snipping Tool, Print Screen, a screen recorder), the PNG will land in the same visual state and be a tenth of the size. If the BMP is going into a print pipeline that specifically asks for BMP (rare, but it exists in some legacy CAD and embroidery workflows), keep the BMP. If the destination is anything modern — web, email, chat, a CMS upload, a design tool that accepts PNG — convert and use the PNG.
How to use
Drop one or many BMP files
Drag .bmp files into the drop zone. BMP is sometimes called 'Windows bitmap' or 'device-independent bitmap' — both are accepted. Files up to 50 MB each process locally.
Wait for the compression
PNG uses deflate compression, which typically shrinks BMP by 70 to 90 percent. A 4 MB screenshot becomes a 400 KB PNG with no quality loss because BMP is uncompressed at the pixel level.
Download the PNGs
Each conversion is near-instant. Downloads are individual by default; switch to zip mode for batches to keep your Downloads folder tidy.
Frequently asked
Is the PNG identical to the BMP at the pixel level?
Yes — BMP and PNG are both lossless formats, so every pixel round-trips. The only thing that changes is the container; the visible image is bit-identical.
Why are BMP files so large?
BMP stores raw pixel data with optional run-length encoding but typically no real compression. A 1920x1080 24-bit BMP is roughly 6 MB; the same image as PNG is usually 400 KB.
Does this handle 32-bit BMPs with alpha?
Yes — the alpha channel is preserved in the PNG output. 32-bit BMPs from Windows screenshots and screen-recording tools round-trip with transparency intact.
Can it convert RLE-compressed BMPs?
Will older versions of Windows still open the PNG?
PNG has been supported by every Windows version since Windows 98. The PNG output is more compatible than the BMP input across web browsers, chat apps, and mobile platforms.
Limitations
- No compression savings on flat-color imagesBMP screenshots of UIs compress extremely well because of large flat regions. Photos compress less dramatically, but PNG is still 30 to 50 percent smaller than BMP for most camera images.
- No palette optimizationIndexed BMPs (8-bit or 4-bit) are decoded to full RGB before re-encoding as 24-bit PNG. The output is slightly larger than a hypothetical palette-preserving path, but compatible with more viewers.
- Output is always 24-bit or 32-bit PNGThe converter does not produce indexed-color PNGs. For files intended for very-low-bandwidth delivery, run the output through a PNG optimizer that supports palette mode.
Platform notes
- macOS
- macOS Preview opens BMP since 10.10 Yosemite. Earlier versions needed a Quick Look plugin. The PNG output opens in every Mac viewer without any codec installed.
- Windows
- MS Paint and every Windows image viewer opens BMP natively because it is the Windows bitmap format. The PNG output is the right pick for web uploads and email attachments where BMP is rejected.
- Linux
- GIMP, ImageMagick, and every GTK/Qt image viewer open BMP. For command-line batch conversion, ImageMagick's `convert input.bmp output.png` does the same job as this browser tool.
- iOS
- iOS Photos cannot import BMP directly. The PNG output is the standard format that iOS handles. AirDropping a BMP file to an iPhone usually fails unless the source app rewraps it first.
- Android
- Android gallery apps rarely preview BMP. PNG is the format every Android image viewer, messaging app, and CMS handles natively. Conversion via this tool is the standard fix.