Why is the PNG smaller than the BMP?

BMP stores pixels without compression. PNG applies lossless DEFLATE, so identical image data is packed into far fewer bytes. Flat color areas shrink the most.

Does the image lose any quality?

No. PNG is lossless, so every pixel comes through exactly as it was in the bitmap. The conversion changes the container and compression, not the picture.

What happens to transparency?

A 24-bit BMP has no alpha channel, so the PNG comes out fully opaque. A 32-bit BMP that carries per-pixel alpha keeps that transparency in the PNG.

Can I convert several bitmaps at once?

Yes. Drop as many as you like; each is converted separately and added to the list, and the Download all button packs them into one zip.

Do my files get uploaded anywhere?

No. Decoding and PNG encoding run entirely in your browser, so the bitmaps never leave your device.

BMP to PNG

Re-encodes your BMP as a compressed, web-friendly PNG.

What this does

A BMP file stores every pixel uncompressed, one row at a time, which is why bitmaps balloon to several megabytes even for a plain screenshot. PNG keeps the same pixel values but runs them through lossless DEFLATE compression, so the converted file is usually a fraction of the size with no change to what you see.

This converter reads each bitmap in the browser, paints it onto a canvas, and re-encodes the result as PNG. The pixels stay intact and any per-pixel alpha that a 32-bit BMP carries is preserved in the PNG. Nothing is uploaded; the decoding and encoding happen on your own machine.

How it works

1Drop your BMP files, or click to pick them.
2Each one is re-encoded to PNG and listed with its new size.
3Download a file on its own, or grab the whole batch as a zip.

Built on web standards

Built with standard browser APIs — no third-party libraries.

Frequently asked questions

Related tools

All Convert image →

HEIC to JPGConvert iPhone HEIC photos to JPG. Decodes each HEIC and re-encodes it as a lossy JPG.WEBP to PNGConvert WebP images to PNG. Transparency stays intact.WEBP to JPGConvert WebP images to JPG. JPG is lossy and has no alpha, so transparent areas are flattened onto white.PNG to JPGConvert PNG images to JPG. JPG is lossy and has no alpha, so transparent areas are flattened onto white.HEIC to PNGConvert iPhone HEIC photos to PNG. The output is lossless, so full quality stays.PNG to SVGTrace PNG images into SVG vectors. Works best on logos and silhouettes, not photos.