BMP3 to ICO Converter
FileFlip converts BMP3 to ICO entirely inside your browser, using ImageMagick compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a BMP3 file to ICO?#
- Drop your BMP3 file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to ICO and the conversion starts on its own. FileFlip downloads 14.1 MB of WebAssembly the first time and nothing after that, then runs ImageMagick on your own machine.
- Save the ICO file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting BMP3 to ICO lose quality?#
No. Converting BMP3 to ICO writes the data out again without discarding any of it, so nothing that was in the BMP3 file is lost on the way. What changes is the size of the file, not what is inside it.
Is it safe to convert BMP3 files online?#
Yes, because nothing is uploaded. FileFlip converts BMP3 files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What BMP3 to ICO actually does to the file#
Converting BMP3 to ICO runs on ImageMagick, downloads 14.1 MB of WebAssembly the first time and nothing after that, writes the data out again without discarding any of it.
| Engine | ImageMagick |
|---|---|
| Conversion path | One step: BMP3 → ICO |
| Downloaded to your browser | 14.1 MB, once, then cached by your browser |
| Quality | Lossless |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What is a BMP3 file?#
BMP3 is ImageMagick's name for a Windows bitmap saved with the 40-byte BITMAPINFOHEADER that Windows 3.0 introduced in 1990, an encoding choice rather than a different file format, and it's the header structure the overwhelming majority of ordinary .bmp files already use.
Choose BMP3 for maximum compatibility, since it's the header format nearly all BMP-reading software expects.
Convert away from BMP to PNG when the image needs transparency, or when you want lossless compression smaller than BMP3's largely uncompressed pixel data.
What is an ICO file?#
An ICO file packs several copies of the same picture, each a different pixel size and color depth, into one Windows icon container so the operating system can pick whichever copy fits the taskbar, the desktop, or a File Explorer thumbnail.
Use ICO for Windows application icons, desktop shortcuts, and website favicons, where the operating system or browser needs to choose the right size automatically.
Convert ICO to PNG when the image needs to be edited freely, resized to a size the icon doesn't already contain, or used anywhere other than Windows or a browser favicon.
BMP3 to ICO questions people ask#
What is BMP3?
BMP3 is ImageMagick's name for a standard Windows bitmap written with the 40-byte BITMAPINFOHEADER, not a separate format. It's the same header structure that almost every ordinary .bmp file already uses.
Is BMP3 the same as a normal BMP file?
Yes, in practice. Windows has used the BITMAPINFOHEADER as its default bitmap header since Windows 3.0 in 1990, so a plain .bmp saved by most modern software is already what ImageMagick calls BMP3.
Does BMP3 support transparency?
No. The BITMAPINFOHEADER that BMP3 writes has no alpha channel; that was added in later Windows header versions. A BMP3 file is always fully opaque.
What is an ICO file?
An ICO file is the icon format Windows uses for application icons, desktop shortcuts, and browser favicons. Rather than holding a single picture, it bundles multiple versions of the same image at different pixel sizes and color depths so the system can display whichever one fits the context.