BMP → PNG

Convert BMP to PNG

Shrink uncompressed Windows bitmaps dramatically without losing a single pixel. Free, unlimited, nothing uploaded.

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BMP and every other format · no size limit · never uploaded

Check it yourself

Your images never leave this tab.

Open your browser's developer tools, switch to the Network tab, and convert a file. You will see the encoder and its WebAssembly module load from this domain the first time, and then nothing — no upload, no image data, no request carrying your file anywhere. Turn off your Wi-Fi after the page loads and it still works.

Frequently asked questions

How do I convert BMP to PNG for free?
Drop your .bmp files onto the box at the top of this page — PNG is already selected — press Convert, and download the results. No account, no watermark and no daily limit, because the conversion runs on your own machine rather than on a server.
Is any quality lost?
None whatsoever. This is the rare conversion with no trade-off at all. BMP stores raw pixels and PNG stores compressed pixels, but PNG's compression is lossless — the decoded image is bit-for-bit identical. You get exactly the same picture in a much smaller file.
How much smaller will the PNG be?
Usually a great deal. A BMP stores every pixel as raw bytes with essentially no compression, so a 1920 by 1080 screenshot occupies around 6 MB regardless of what it shows. The same image as a PNG is often a few hundred kilobytes. Reductions of five to twenty times are routine, and screenshots and flat-colour graphics do best of all.
Why does BMP produce such enormous files?
Because it was designed in 1986 for Windows to hand pixels straight to a display, not to store or transmit them. Compression was not the point — direct memory layout was. The format still turns up constantly in output from scanners, old Windows utilities, embedded devices and industrial software, all of which is why people end up needing this conversion.
Should I convert to PNG or JPG?
PNG for screenshots, diagrams, logos, scanned text and anything with hard edges or flat colour — it is lossless and it compresses that material extremely well. JPG for photographs, where it will be considerably smaller than the PNG and the lossy compression suits continuous tone.
Is transparency preserved?
If the BMP has any, which is uncommon. Most BMP files are fully opaque — the format's alpha support is a later addition that many writers never used. Where alpha is present it transfers to PNG's 8-bit alpha channel intact.
One of my BMP files will not convert. Why?
BMP has a long tail of unusual variants — exotic bit depths, RLE compression, OS/2 headers — and decoding here relies on your browser, which handles the common cases and rejects the obscure ones. A file that fails is almost always one of those variants or a truncated download. Re-saving it from an image editor as a standard 24-bit BMP will fix it.

Other conversions

Each converter opens with the right output format already selected, so the file you drop comes back in the format you came for.

Convert WebP to another format

Convert images to WebP

Convert to PNG or JPG

Convert your images without handing them over.

No account, no upload, no limit on how many files you throw at it.

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