Convert BMP to PNG Online Free

Q: How much smaller will my BMP get as a PNG?

Typically 50-80% smaller. PNG uses lossless compression, so the image stays pixel-for-pixel identical while the file shrinks dramatically.

BMP files are huge because they are uncompressed. AllConvert converts BMP to PNG with zero quality loss — typically shrinking the file by 50–80% — right in your browser.

Why convert BMP to PNG?

BMP stores every pixel uncompressed, so even a modest screenshot can weigh several megabytes. PNG stores the exact same pixels with lossless compression — the image is bit-for-bit identical, but the file is typically 50–80% smaller. PNG is also far more widely supported on the web, in chat apps and in email, where many services reject or mangle BMP attachments.

Truly lossless

Unlike converting to JPG, converting BMP to PNG loses nothing: every pixel is preserved exactly. That makes it the right choice for screenshots, diagrams, scans and any image you may want to edit later. If the image is a photograph and you want the smallest possible file, converting to JPG or WEBP shrinks it much further at a small quality cost.

Where do BMP files come from?

Old versions of Microsoft Paint, Windows screenshot tools, scanners and many legacy programs still produce BMP files. Converting them to PNG modernizes the file without touching the image itself.

How to convert

Drop your BMP file into the converter box at the top of this page, or click the box to browse for it.
The conversion to PNG starts immediately and runs entirely on your device.
Click the download button that appears to save your PNG.

Conversion happens entirely on your device — no upload, no account — and it works the same on a phone or a desktop, in Chrome, Firefox, Safari, or Edge.

Need a different format? Open the full converter

The technical difference

A BMP file stores pixel data almost exactly as it sits in memory: three or four bytes per pixel, row after row, with no compression step at all (BMP has an optional RLE mode, but almost nothing actually writes files that use it). That's why a 1920x1080 screenshot can hit 6MB or more as a BMP. PNG runs the same pixel data through DEFLATE — the same compression algorithm behind zlib and gzip — plus a per-row filtering step that makes flat-color regions and screenshots compress especially well. Neither format touches the color values themselves; the pixels are identical, only the container and the compression change.

Frequently asked questions

How much smaller will my BMP get as a PNG?
Typically 50–80% smaller. PNG's lossless compression shrinks the file dramatically while the image stays pixel-for-pixel identical.

Does BMP to PNG conversion lose quality?
No. Both formats are lossless, so the PNG contains exactly the same pixels as the BMP — only the file size changes.

Why won't websites accept my BMP file?
Many websites and apps only accept modern formats like PNG, JPG and WEBP. Converting your BMP to PNG makes it universally accepted with no quality loss.