Format comparison
BMP vs ICO
How do BMP and ICOcompare? Here's everything you need to know to choose the right format — and how to convert between them.
.bmp
Full guide →Bitmap Image File
BMP is an uncompressed raster image format native to Windows. While it produces very large files, BMP preserves every pixel with zero quality loss, making it useful for raw image data and legacy applications.
.ico
Full guide →Icon File Format
ICO is the icon file format used by Windows for application icons and website favicons. It can contain multiple image sizes and color depths in a single file.
| Specification | BMP | ICO |
|---|---|---|
| Full name | Bitmap Image File | Icon File Format |
| Extension | .bmp | .ico |
| MIME type | image/bmp | image/x-icon |
| Category | Image | Image |
| Developer | Microsoft | Microsoft |
| Year introduced | 1986 | 1985 |
| Compression | Lossless | Lossless |
BMP advantages
- Zero quality loss — completely uncompressed
- Simple format, easy to read and write
- Native Windows support
- No compression artifacts
BMP limitations
- Very large file sizes
- No transparency support in most versions
- Not suitable for web use
- Outdated format for most modern applications
ICO advantages
- Multiple sizes in one file
- Standard for Windows icons and favicons
- Widely supported by all browsers
- Small file sizes
ICO limitations
- Limited to small image dimensions
- Primarily Windows-focused format
- Being replaced by PNG favicons in modern web
- Complex internal structure for a simple purpose
Which should you use?
Both BMP and ICO have their strengths. BMP excels at legacy windows applications, while ICO is better for website favicons.
Best uses for BMP
Legacy Windows applications
Raw image data storage
Intermediate format during editing
Embedded systems and simple displays
Best uses for ICO
Website favicons
Windows application icons
Desktop shortcuts
Taskbar and system tray icons
Convert between BMP and ICO
Need to switch formats? Convert for free with SquishConvert.