BMP To ICO Converter

ICO files are used for application icons in Windows — desktop shortcuts, taskbar icons, executable file icons, and installer icons all use ICO format. They are also used for website favicons displayed in browser tabs and bookmarks. An ICO file can bundle multiple image sizes in a single container, allowing the OS or browser to automatically select the most appropriate resolution for each display context.

No. BMP files are standard raster images and cannot be used directly as Windows application icons or favicons. Windows and browsers specifically expect ICO format for icon display. BMP files must be converted to ICO to function as application or system icons. Converting packages the artwork into a proper icon container with the multi-resolution bundle the OS expects for reliable display across all contexts.

No — the converter preserves clarity and optimizes the image for icon usage. Modern ICO files embed PNG data internally, so each bundled size is stored losslessly with full color and transparency preserved. For the best quality output, start with a high-resolution BMP, ideally 256×256 pixels or larger, so each smaller size is downscaled from a high-quality source rather than upscaled from a low-resolution one.

Yes. All processing happens securely in your browser and files are never sent to any server. Conversion runs entirely on your device using client-side JavaScript, so your artwork remains completely private. The tool works offline once the page has loaded and there is zero data collection. Your brand artwork and application icons stay yours from start to finish with no uploads and no tracking.

Yes. Batch conversion is supported, allowing multiple BMP files to be converted in one operation. Each BMP produces its own ICO file. You can then download them individually or bundled together in a ZIP archive. This is useful for converting an entire set of icon images for an application with multiple icon needs in a single efficient operation.

For website favicons, include 16×16 and 32×32 at minimum — adding 48×48 provides broader browser support. For Windows application icons, include 16×16, 32×32, 48×48, and 256×256 to cover taskbar icons, file Explorer thumbnails, and high-DPI displays. Including all available sizes creates the most versatile ICO, though the file size increases slightly with each additional resolution bundled.

Yes. Modern ICO files embed PNG data internally, and PNG fully supports alpha channel transparency. Transparent areas in your source BMP are preserved cleanly in the ICO output, so the icon appears with a transparent background against any OS theme or background color — no solid fill box around the artwork. This is essential for icons that need to look clean on both light and dark Windows themes.

Upload the converted ICO file to the root directory of your website as favicon.ico. Most browsers will automatically detect and display it without any additional code. For best results, also add a link tag in your HTML head: <link rel="icon" type="image/x-icon" href="/favicon.ico">. Using both methods ensures maximum compatibility across all browsers including legacy ones.

Yes. The converter is fully responsive and works on smartphones, tablets, and desktop computers. Conversion runs locally in your device's browser. BMP files can be large, so processing big source files may be slightly slower on lower-powered mobile devices. The ICO output is typically small regardless of input size, so download is always fast on any device.

No. The converter never adds watermarks, logos, or any branding to your icons. The output ICO contains only your original artwork. There are no usage limits, no sign-up requirements, and no hidden fees. Convert as many BMP files to ICO as you need, as often as you need, and the resulting icons are entirely yours to deploy in your applications and websites.

For best results, use a source BMP of at least 256×256 pixels. This ensures each bundled size in the ICO is created by downscaling from a high-quality source, which produces sharper results than upscaling a small image. For very high-DPI displays or future-proofing, starting at 512×512 or 1024×1024 provides even more headroom. Icons created from large high-quality sources look significantly better than those upscaled from small originals.