Convert BMP to JPG — shrink bitmaps without uploading them
A BMP file is essentially raw pixels on disk — the format Windows has carried since the beginning, typically with no compression at all. That is why a single scan or Paint export can weigh tens of megabytes and get bounced by every email server and upload form it meets. Converting to JPG fixes the size problem instantly, often shrinking files by 90% or more with no visible change for photos and scans. The conversion here runs in your browser: your BMPs are decoded locally and re-encoded with the mozjpeg WebAssembly encoder, so old family scans and documents never travel to a third-party server.
How it works
- Drop .bmp files below — even very large ones are fine.
- Choose the JPG quality; 80–90 works well for scans and photos.
- Download each JPG and marvel at the size difference.
Frequently asked questions
Why are BMP files so enormous?
Most BMPs store every pixel uncompressed — three or four bytes each, no exceptions. A 4000×3000 scan is roughly 36 MB regardless of content. Modern formats like JPG compress intelligently, which is why the same image can drop to a megabyte or two.
Will I lose quality converting BMP to JPG?
JPG is lossy, so technically yes — but for photos and scans at quality 85+, the difference is invisible in normal use. For line art, diagrams, or screenshots with text, consider BMP to PNG instead, which is lossless.
Do you upload my scans to convert them?
No. The whole conversion happens in your browser via WebAssembly. That is especially relevant for BMPs, which are often scans of personal documents — they stay on your device from start to finish.
Can I convert many BMPs at once?
Yes, batch conversion is supported — drop as many as you like. Since processing is local, the only practical limit is your device’s memory, and each finished JPG downloads as it completes.