Why a BMP is so large
A .bmp file writes down the color of every pixel, one after another, with no compression at all. A 4000 by 3000 photo takes about 36 MB that way. PNG stores the same pixels and packs them, which is why the file you download here is typically a fifth of the original or smaller, with nothing thrown away.
Drop your .bmp files and the conversion happens in your browser. No upload, no waiting on a queue.
Where BMP files come from
- Windows Paint saved to .bmp by default for years, and old documents are full of them.
- Scanners and fax software on office machines still produce BMP output.
- Screen capture utilities from the XP era wrote .bmp straight to disk.
- Programming and game assets use BMP because the format is trivial to parse.
What the conversion changes
Nothing in the picture. PNG is lossless, so every pixel arrives exactly as it left the BMP, at a fraction of the file size. Colors, sharpness and dimensions stay identical.
Most BMP files have no transparency to worry about. The 32-bit variety can carry an alpha channel, and where your browser reads it, PNG keeps it.
Frequently asked questions
Is anything uploaded?
No. Your browser decodes and re-encodes the image locally. Once this page has loaded you can work offline.
Does the image lose quality?
Not a pixel. Both formats are lossless, so this is a repack rather than a re-encode.
How much smaller will the PNG be?
Photos usually land somewhere between a fifth and a half of the BMP. Screenshots and flat graphics compress far harder, often to a few percent. Each download lists both sizes so you can see what you got.
Can I convert several files at once?
Drop the whole batch. Every file gets its own download button, and the last button zips them together.
My BMP is enormous. Will this work?
Large files run in your device's memory, so a desktop handles more than a phone. Around 50 MB is where mobile browsers start to struggle.
Should I use JPG instead?
Only if the file needs to be small enough for an attachment and the picture is a photograph. For screenshots, diagrams and anything with text, PNG stays sharp where JPEG smudges. The GIF and JPG converters sit next to this one when you need them.