How do I convert BMP to ICO?

Add your BMP file to the upload area above, then press Convert. The ICO file downloads straight to your device. You do not need an account, and there is no watermark.

Are my files uploaded to a server?

No. This conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can even disconnect from the internet after the page loads and it will still work.

Does converting to ICO reduce quality?

No. ICO is a lossless format, so the conversion preserves exactly what is in your BMP file. Note that it cannot recover detail that was already discarded when the BMP was first created — a lossless container does not undo earlier compression.

How large a file can I convert?

Up to 120 MB per file for this conversion. Because the work happens in your browser, the practical limit is your device's memory — larger files work on a desktop with plenty of RAM and may fail on an older phone.

Can I convert several files at once?

Yes. Add as many as you like and press Convert All. Each file is processed independently, so one failure does not stop the rest, and you can download everything together as a ZIP.

Can I use this on my phone?

Yes. FileTools360 works in mobile browsers on iOS and Android, including choosing files straight from your camera roll. Very large videos may run out of memory on a phone — those are better converted on a laptop.

ImageLosslessRuns in your browser

BMP to ICO Converter

Turn BMP files into ICO in a couple of clicks. Uncompressed raster bitmap. Large but simple. Multi-resolution icon container for favicons and apps. The conversion is lossless — every pixel, sample or byte in the source is preserved.

On your deviceNever uploadedGone when you close the tabHow this works

Drop your files here

BMP files (.bmp, .dib) · up to 120 MB each

or paste files from your clipboard

Ready when you are

Drop a BMP file above and FileTools360 will turn it into ICO — right here on your device, without uploading anything.

⌘K to search converters

How to use it

1
Add your BMP files
Drag them onto the upload area, choose them from your device, or paste them from your clipboard. You can queue several at once.
2
Adjust the settings if you want to
The defaults suit most people. Open Advanced to control dimensions, rotation and metadata removal.
3
Convert and download
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.

BMP and ICO explained

BMP stores pixels essentially raw, with little or no compression. A 1920×1080 BMP is around 6 MB regardless of what the picture contains, because every pixel takes the same space whether it is part of a gradient or a flat colour.

ICO is a container that holds several versions of the same icon at different sizes, so the operating system or browser can pick the one that fits. It is capped at 256×256 pixels.

Where BMP files come from: Legacy Windows software, some scientific and industrial imaging tools.
Where ICO is used: Website favicons and Windows application icons.

BMP vs ICO

The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.

BMP compared with ICO
Property	Source	Target
Compression	Uncompressed	Lossy or lossless
Transparency	No	Yes
Animation	No	No
Introduced	1990	1985
Browser support	Broad, though rarely the best choice today.	Browsers and Windows. Sizes are capped at 256×256.

BMP is stronger at: Trivially simple to read and write. No compression artefacts whatsoever. Still readable by very old software.
ICO is stronger at: Holds multiple resolutions in one file. The format browsers expect for favicon.ico. Supports transparency.

Why convert BMP to ICO?

People make this switch when they run into the limits of BMP: almost always — PNG gives you the same lossless fidelity in a fraction of the space. ICO is the better fit when you are making a favicon or a Windows application icon.

There is also a size argument: BMP stores data with little or no compression, so the ICO version is normally dramatically smaller for the same content.

BMP limitations that prompt the switch: Enormous files. No standard support for transparency in most variants. Effectively unusable on the web.
What you give up: Capped at 256×256. Not a general-purpose image format.

Does converting BMP to ICO reduce quality?

Both formats store the content without discarding data, so this conversion preserves it exactly. The file size may change because the two formats compress differently, but the content itself is unaffected.