Free online ICO to BMP converter

Some Windows utilities, legacy applications, and image editors accept BMP but not ICO files. Converting the icon produces a bitmap that can be edited, printed, or archived by software without ICO support.

What the ICO format is

ICO is the Windows icon container format used for application, folder, shortcut, and website icons. One file can contain several raster images at different dimensions and color depths, such as 16×16, 32×32, 48×48, and 256×256 pixels. Larger entries may use PNG compression, while older entries commonly use Windows bitmap data and a transparency mask.

Windows applications, resource compilers, icon editors, design software, and some image editors create or read ICO files. You commonly encounter them in application folders, desktop shortcuts, software packages, and website favicons.

What the BMP format is

BMP, or bitmap, stores pixel data in a Windows-compatible raster format. BMP is straightforward to open and edit, supports direct pixel-level work, and is accepted by many Windows utilities, image editors, documentation tools, and older technical applications. It can use uncompressed data or limited compression such as RLE, but uncompressed BMP is the usual output.

BMP files are often much larger than ICO files. Standard 24-bit BMP has no alpha channel, and support for transparency in 32-bit BMP varies between programs; some preserve or interpret the alpha channel, while others ignore it. Use BMP when the receiving application requires it, rather than assuming it is a smaller or more modern image format.

How to convert ICO to BMP

Convert on 101convert.com

1. Open the ICO-to-BMP converter on 101convert.com. It can be used for free without installing software.
2. Upload the .ico file.
3. If the file contains several embedded images, select the required size or image entry when the converter provides that option. Choose the largest suitable entry when detail matters.
4. Set the output format to BMP and start the conversion.
5. Download the .bmp file and verify its dimensions, color depth, background, and transparency in the program that will use it.

Convert with GIMP

1. Open the ICO file through File → Open.
2. If GIMP presents multiple embedded images or imports them as layers, select the required size. Export only that image or layer if necessary.
3. Choose File → Export As, specify a filename ending in .bmp, and select Export.
4. In the BMP export dialog, choose the required color depth and confirm the export. Use 24-bit output for broad compatibility when transparency is not required.

Convert with ImageMagick

To inspect the images stored in an ICO file, run:

magick identify icon.ico

To export a particular embedded image, use its zero-based index:

magick icon.ico[0] output.bmp

Replace [0] with [1] or another available index to select a different size. The exact index depends on the entries stored in the file, so inspect the file before converting when the source contains multiple resolutions.

Quality and compatibility limits

Conversion does not create missing detail. Exporting a 16×16 entry produces a 16×16 BMP, and enlarging it causes pixelation; select a 256×256 or other larger entry when available.

ICO transparency may consist of an alpha channel, a transparency mask, or both. A BMP export can lose that transparency, render transparent pixels against a background, or preserve alpha that the target program ignores. If the receiving software does not explicitly support alpha-enabled BMP files, export to 24-bit BMP over a solid background.

An ICO can include different artwork at each size, not merely scaled copies, so selecting the correct embedded entry affects the result. If the target application accepts PNG instead, PNG generally preserves transparency with a smaller file; BMP remains appropriate when compatibility with a BMP-only application or device is the requirement.