Convert BMP to ICO Online — Free
Runs 100% in your browser — your files never leave your device.
Icons generated by older tooling often arrive as BMP. This converter re-encodes the bitmap as PNG and wraps it in a proper ICO container, scaling to the 256×256 icon limit when needed — all locally in your browser.
How it works
- 1
Drop your BMP file
Drag a BMP into the box, or click to browse. Nothing is uploaded.
- 2
Convert to ICO
The bitmap becomes a PNG inside a standard icon container.
- 3
Download the result
Save the ICO with one click — ready for favicons and shortcuts.
About this tool
Converting BMP to ICO
A BMP file bmp stores pixels essentially uncompressed — enormous files, zero quality loss, and roots deep in legacy windows software that only accepts it.. ICO ico is the windows icon container: a single file holding the same image at several sizes so icons render crisply at every scale. Converting moves your image from the first set of trade-offs to the second: the uncompressed bulk shrinks, transparency survives where supported, and pixel data is re-mapped to the target format exactly.
What to check after converting
Open the result and check the two things conversion can change: transparency and size. Transparency is carried over exactly where the target format supports it. Your original file stays untouched on your device either way, and the download is a brand-new file.
Frequently asked questions
Is this conversion lossless?
Yes — both BMP and ICO store pixels losslessly, so the conversion moves your image between formats without touching a single value. The file size changes; the pixels do not.
Is my image uploaded anywhere?
No — the conversion runs entirely in your browser. The image is processed on your device and never sent to any server, which you can verify by disconnecting after the page loads.
Why convert BMP to ICO instead of the other way around?
The direction follows what the destination needs: Windows icons and favicons versus legacy Windows compatibility. Converting back is always available — but each lossy hop re-encodes the image, so keep the highest-quality format as your working copy and convert toward the destination.