Open .BMP files online
A .bmp file is a raster image in the Windows Bitmap format. BMP stores pixel data largely uncompressed, which makes it simple to read and write but produces very large files compared to PNG or JPEG. It is a legacy format still encountered in Windows assets, icons, and older software.
Because BMPs are uncompressed, they are lossless but wasteful — a BMP can be many times the size of the same image as a PNG. They are rarely the right choice for delivery today, but they are trivial to view and decode.
What is a `.bmp` file?
A BMP file has a header describing the image dimensions and color depth, followed by the raw pixel grid (usually bottom-to-top). There is little to no compression in the common forms, so file size grows directly with pixels and color depth.
MIME type: image/bmp. BMP supports 1-bit to 32-bit color (the 32-bit form includes an alpha channel) but no animation.
- Windows wallpapers and system graphics
- Icons and cursors
- Legacy application assets
- Uncompressed intermediate image storage
How to open a `.bmp` online
Open the zip viewer in a new tab, then drop your .bmp onto the page — or click to browse for it, or paste a URL. The file opens in the image viewer, read entirely on your device.
- Drag your
.bmponto the page — or click to browse, or paste a URL. - It opens immediately in the image viewer. No install, no sign-up.
- Read, search, or copy it. Your file never leaves your browser.
Open `.bmp` without uploading
Most "open bmp online" sites work by uploading your file to a server and processing it there. ZipTool does the opposite: it loads its parser once, then reads your .bmp locally in the browser tab. The contents stay on your device.
You can prove that in seconds. Open the page, press F12 for DevTools, switch to the Network tab, and open your file — no request carrying the file's contents is sent. You can also turn off Wi-Fi after the page loads and the file still opens. See security and privacy for the full picture.
Frequently asked questions
How do I open a .bmp online?
Drag the .bmp onto the page (or click to browse, or paste a URL). It opens in the image viewer immediately. The file is decoded entirely in your browser and never uploaded.
Can I view a .bmp without uploading it?
Yes. ZipTool decodes the image locally in your browser tab — no upload, no server-side copy. Confirm it with DevTools (F12, Network tab) while opening the file, or by turning off Wi-Fi after the page loads and verifying the image still displays.
Why are .bmp files so large?
Because BMP stores pixels largely uncompressed, file size grows directly with resolution and color depth — a few megapixels can mean tens of megabytes. PNG compresses the same pixels losslessly into a much smaller file, which is why BMP is rarely used for delivery today.
Does BMP lose quality?
No. Uncompressed BMP is lossless: it stores every pixel exactly. The drawback is size, not quality. (Some rare compressed BMP variants exist, but the common forms are uncompressed.)