Image format
What is a BMP file?
BMP is an old Windows bitmap format that stores pixel data with little or no compression — simple, but large.
BMP dates back to the earliest versions of Microsoft Windows, where it was used as the native format for storing raw pixel grids with minimal processing overhead — appropriate for the modest CPUs of the era, but wasteful by modern standards. Because it stores pixels close to as-is, a BMP file opens instantly and never introduces compression artifacts, but it can be five to ten times larger than a JPEG of the same image. Today it mostly survives in legacy Windows software and a few specialized pipelines that specifically want uncompressed pixel data.
How to open a BMP file
BMP files open readily in Windows Photos, macOS Preview, Any web browser. For real editing rather than just viewing, reach for Photoshop, GIMP, MS Paint.
Strengths & limitations
Good for
- dead-simple, well-documented structure
- no compression artifacts
Watch out for
- huge file sizes compared to almost any modern format
Convert BMP files
Orbfile can convert BMP both ways, entirely in your browser — pick a direction below:
Frequently asked questions
What does a BMP file contain?+
BMP is an old Windows bitmap format that stores pixel data with little or no compression — simple, but large.
Can I convert BMP for free?+
Yes — Orbfile's image converter handles BMP for free, with no file limit, watermark, or account, and it runs entirely in your browser.
Is converting a BMP file safe and private?+
Yes. Orbfile processes BMP files locally on your device using WebAssembly — nothing is uploaded to a server, so there's nothing to leak or store.
Who created the BMP format?+
BMP was developed by Microsoft, first released around 1990.
Browse the full file format guide.