Compress BMP Images Online

Compress BMP files without trading away image quality

BMP is one of the few image formats that barely bothers to compress anything — it mostly just writes every pixel straight to disk. That makes compressing a BMP different from compressing a JPEG or a WebP, where you are trading away some quality for a smaller file. With BMP, most of the size was never buying you anything in the first place, so compressing it is close to pure upside: the bulk goes, and there is far less need to sacrifice quality to get there.

Where the savings actually come from

How much a BMP shrinks depends on what is in it. Flat, repetitive content — screenshots, scanned documents, simple graphics — compresses dramatically, because that repetition is exactly what compression removes. One measured screenshot dropped from 6.22 MB to well under 1% of that size, with every pixel identical afterward. A detailed photograph has less repetition to remove, so it saves less — but it still shrinks, and you are not choosing between size and quality the way you would with a lossy format.

Why your BMP was so large in the first place

BMP dates from an era when disk space mattered less than simplicity, so it stores raw pixel data with little or no packing. That means the file size depends almost entirely on the image's dimensions rather than on how complicated the picture is: a plain white 4000-pixel-wide image and a detailed photograph of the same size take up roughly the same room. It is why a single screenshot saved as BMP can be larger than an entire folder of JPEGs.

Nothing changes except the file size

The dimensions stay exactly as you uploaded them, and the image is not rescaled, cropped or converted behind your back. What comes back is the same picture, taking up less room.

Batches, not one file at a time

Upload a whole folder and each BMP is compressed on its own, so a set of screenshots or scanned pages does not have to be done one by one.

Nothing to install, nothing to sign up for

Compression runs in your browser, so it works the same on a phone as on a desktop. There is no account, no watermark and no email step, and files are removed from the server within the hour.

What you get

Large size reductions without the quality trade-off lossy formats force on you
Dramatic savings on screenshots, scans and flat graphics
Original dimensions preserved — nothing rescaled or cropped
Whole folders compressed in one go, each file handled individually
Free, with nothing stored for longer than an hour

What's next?

If you are keeping these images long term, converting is often better than compressing: Compress PNG covers the format most people move BMP files to, and Compress JPG suits photographs where a smaller file matters more than exact pixels. Need a document instead of loose images? JPG to PDF turns a batch into one shareable file.

Frequently Asked Questions

For most of the size reduction, no. BMP's size comes mainly from storing every pixel with no compression at all, so removing that waste does not require throwing away picture detail the way shrinking a JPEG does.

BMP was never designed to compress anything — it writes raw pixel data with little or no packing, so its size depends mostly on the image's dimensions rather than what is actually in the picture.

It depends on the content. Flat or repetitive images — screenshots, scans, simple graphics — shrink the most, often dramatically. Busy, detailed photographs shrink less, since there is less repetition to remove, but they still get smaller.

Yes — upload a batch and each file is compressed individually rather than one at a time.

No. Compression reduces file size only; the picture itself and its dimensions stay as you uploaded them.

Up to 100 files per session, each up to 15 MB. If you have more, refresh the page and run another batch — there is no daily cap.