Why BMP files are so large
BMP, the Windows bitmap format, usually stores every pixel uncompressed: three bytes of color per pixel, row after row. A 1920 by 1080 image is therefore about 6 MB no matter what it shows. That simplicity made BMP popular in early Windows software, scanners and screen capture tools, but it is wasteful for storing or sharing images today.
JPG compresses photos and scans extremely well. Converting a BMP to JPG commonly reduces the file by 90 percent or more while looking the same, which makes the image practical to email, upload or publish.
BMP vs JPG at a glance
| Feature | BMP | JPG |
|---|---|---|
| Full name | Bitmap Image File (Device Independent Bitmap) | JPEG (Joint Photographic Experts Group) |
| Type | Raster image | Raster image |
| Introduced | Mid 1980s (Windows and OS/2) | 1992 |
| Created by | Microsoft and IBM | Joint Photographic Experts Group (ISO/IEC 10918) |
| Compression | Usually none (optional RLE) | Lossy (DCT based) |
| Transparency | Rare, only in some 32-bit files | No |
| Animation | No | No |
| Color depth | 1 to 32 bits per pixel | 24-bit, about 16.7 million colors |
| Best for | Legacy Windows software and raw pixel data | Photos and other realistic images |
| Support | Widely readable, but files are very large | Universal: every browser, operating system and editor |
| MIME type | image/bmp | image/jpeg |
How to convert BMP to JPG
Step 1: Select the BMP
Drop a .bmp file onto the converter. Files from Paint, old scanners and legacy apps all work.
Step 2: Keep JPG selected
JPG is the default target on this page.
Step 3: Convert
The bitmap is decoded by your browser and encoded as a JPEG at quality 92.
Step 4: Save the result
Download the JPG, now a fraction of the original size.
What this BMP converter supports
Common BMP variants
Uncompressed 24 and 32 bit files, palette based bitmaps and RLE compressed bitmaps decode in modern browsers.
Transparency handling
The rare BMPs with alpha are flattened onto white.
Full resolution
No resizing or cropping takes place.
Works offline once loaded
Everything happens locally in the page.
When to convert BMP to JPG
Old scans and archives. Shrink folders of legacy bitmaps so they are easy to back up and share.
Screenshots from old software. Some Windows tools still save captures as BMP.
Sharing by email. A 20 MB bitmap becomes a small attachment.
Web publishing. Browsers can show BMP, but the files are far too heavy for a web page.
JPG or PNG for your bitmap?
If the BMP is a photo or a scanned picture, JPG is the right target: it gives the biggest size reduction with no visible change.
If the BMP is a screenshot, a diagram or pixel art with sharp edges and text, consider PNG instead. PNG is lossless, still much smaller than an uncompressed BMP, and avoids the soft halos JPG compression can add around text.
- Photos and scans: JPG.
- Screenshots, charts, pixel art: PNG.
- Web graphics: WebP after converting.
What you lose, and what you do not
JPG is lossy, so the output is not a bit-for-bit copy of the bitmap. At quality 92 the difference is not noticeable for photographic content. The image keeps its dimensions and orientation.
BMP files rarely carry metadata, so nothing important is lost there. Color depth is converted to standard 24 bit color, which covers the vast majority of bitmaps.
Tips for bitmap conversions
- Convert a sample first and compare it with the original at 100 percent zoom.
- Use the bulk image converter for whole folders of BMP files.
- Very old 1 bit or 4 bit bitmaps convert fine, but JPG is not ideal for them; PNG is usually better.
- Delete the BMP only after checking the JPG opens correctly.
BMP to JPG questions
How much smaller will my file be?
Uncompressed bitmaps often shrink by 90 percent or more as JPG. The exact saving depends on the image content.
Does converting BMP to JPG reduce quality?
JPG is lossy, but at the high quality used here the change is not visible for photos and scans. Use PNG if you need a lossless copy.
Can it open 32 bit BMP files?
Yes. Any alpha information is flattened onto a white background because JPG has no transparency.
Is there a size limit?
No fixed limit, but very large images need enough device memory to decode.
Is my image sent to a server?
No. The conversion runs entirely in your browser.
What is BMP still used for?
Mostly legacy Windows software, some industrial and scientific devices, and embedded systems that want raw, easy-to-read pixel data.