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Turn your BMP images into ICO right in the browser — this tool will shrink each file and hand it back in seconds, with nothing uploaded to any server. BMP is an uncompressed Windows bitmap: every pixel is stored raw, so quality is exact but files are very large. ICO is the Windows icon and favicon format, holding one or more small square images up to 256×256. ICO adds an alpha channel, so you gain transparency support that BMP never had. Free, private, unlimited, and watermark-free.
How to Convert BMP to ICO
Add your BMP files
Drag and drop, or click to browse. You can convert several at once — they are processed together, right here in your browser.
Convert to ICO
Press Convert. ICO is lossless, so every pixel is preserved exactly.
Download
Save each ICO file, or grab them all as a ZIP. Nothing was ever uploaded, so nothing needs deleting.
Why convert BMP to ICO?
The main reason is favicons and Windows application icons, where a compact square with transparency is needed. BMP excels at exact pixel data with zero compression, but when you need transparency, ICO is the better fit. This tool makes that switch instantly, right in your browser.
What happens to quality?
ICO is a lossless format, so the conversion preserves your image exactly — no detail is discarded in the ICO encoding itself.
A note on file size
Expect the ICO file to be noticeably smaller than your BMP.
About BMP
BMP is an uncompressed Windows bitmap: every pixel is stored raw, so quality is exact but files are very large. Best for exact pixel data with zero compression, occasionally required by legacy Windows software.
About ICO
ICO is the Windows icon and favicon format, holding one or more small square images up to 256×256. Best for favicons and Windows application icons, where a compact square with transparency is needed.
Common Uses for BMP to ICO
- Converting BMP to ICO for a project that specifically requires Windows Icon files, where BMP is not accepted.
- Preparing images for design work that needs transparency support.
- Batch-converting a whole folder of BMP images to ICO at once, instead of doing them one at a time.
- Switching a Bitmap export into ICO so it opens correctly in the tools your team actually uses.
- Archiving BMP images as lossless ICO so no further quality is lost over time.
BMP vs ICO: Key Differences
| Aspect | BMP | ICO |
|---|---|---|
| Compression | Lossless | Lossless |
| Transparency | Not supported | Supported |
| Animation | Not supported | Not supported |
| Colour depth | 24-bit uncompressed colour | 24-bit colour with transparency |
| Typical file size | Large | Medium |
| Best used for | exact pixel data with zero compression | favicons and Windows application icons |
Tips & Things to Know
Check the file size after converting
Expect the ICO file to be noticeably smaller than your BMP. If size matters for your use case, the before-and-after figures shown above tell you exactly what changed, so there are no surprises when you upload or share the result.
Add transparency support
Because ICO supports an alpha channel, the result can hold transparency even though BMP itself is always fully opaque. Areas stay on whatever background the BMP shows.
Everything stays on your device
This converter runs entirely in your browser using your own processor. Your BMP files are never uploaded, stored, or seen by anyone, which makes it safe for private photos, client work, and confidential documents. When you close the tab, nothing remains.
The conversion is faithful
ICO is lossless, so every pixel is preserved exactly as it was in your BMP, meaning you do not have to worry about settings — just convert and download.
Frequently Asked Questions
How do I convert BMP to ICO for free?
Add your BMP file above and press Convert. The ICO download appears in seconds. It is completely free, with no signup, no limits and no watermark.
Is my BMP uploaded to a server?
No. The entire conversion runs inside your browser using your device's own processor, so your images never leave your computer. That matters for private photos and confidential work.
Can I convert multiple BMP files at once?
Yes. Add as many as you like and they are converted in one batch, then offered individually or as a single ZIP download.
Will converting to ICO reduce quality?
No. ICO is lossless, so the conversion keeps every pixel. Any quality limit comes only from the original BMP, not from this step.
Does ICO support transparency?
Yes, ICO supports an alpha channel, so transparent areas in your image are preserved.
Why is my ICO file a different size than the BMP?
Different formats compress differently. Expect the ICO file to be noticeably smaller than your BMP.
What is the difference between BMP and ICO?
BMP is an uncompressed Windows bitmap: every pixel is stored raw, so quality is exact but files are very large. ICO is the Windows icon and favicon format, holding one or more small square images up to 256×256. That difference is what this conversion is really about.
Is there a file size limit?
Because processing happens in your browser, very large images depend on your device's memory, but typical photos convert instantly. Nothing is capped by an upload limit.
Do I need to install anything?
No. This works in any modern browser on any device — Windows, Mac, Android or iPhone — with nothing to install.
Is this BMP to ICO converter really free?
Completely free, forever, with no account, no watermark and no hidden premium wall.
100% free · No signup · No watermark · Files never leave your browser
Last updated: July 18, 2026 · FlipMyFormat Convert BMP to ICO
Written and maintained by the FlipMyFormat team · Runs entirely in your browser