BMP to ICO converter
Turn a BMP image into a real multi-size .ico for a favicon or Windows icon. Pick the sizes, fit or crop to square, and download. It all happens in your browser.
BMP to ICO: what to know
BMP is the uncompressed Windows bitmap. Classic .ico files actually store their images as BMP data, but modern icons use PNG inside the .ico because it is far smaller and supports smooth transparency.
Transparency
Most BMP files have no alpha channel, so the icon will be a full square. If your BMP has a solid background colour you want gone, remove it in an editor and save as PNG first.
Tips for a sharp icon
- BMP files are large; a 1024 px BMP can be 3 MB. The resulting .ico will be a few kilobytes.
- If the BMP came from an old icon editor at exactly 16 or 32 px, tick only that size so it is not resampled.
- Use “Stretch” only if the BMP is already square.
Need the whole favicon set (SVG, Apple touch icon, Android icons, manifest)? Drop the same file into the favicon generator. Other converters: PNG to ICO, JPG to ICO, SVG to ICO, WebP to ICO, GIF to ICO, AVIF to ICO.
Questions people ask
How do I convert BMP to ICO?
Drop the .bmp file into the converter, pick the sizes and click Download .ico. The conversion runs in your browser.
Is an ICO file just a BMP?
Not exactly. An ICO is a container with a directory of images. Older icons store each image as BMP pixel data plus a 1-bit transparency mask; modern icons store PNGs instead. This converter writes PNG-based entries, supported by Windows Vista and later and every current browser.
Can I keep a 16-colour or 256-colour look?
The converter writes 32-bit images, which display any palette exactly. A pixel-art BMP converted at its native size keeps its exact colours.