Free Image to ICO Converter

An ICO file is a specialized image format originally developed by Microsoft for Windows icons. Unlike standard image formats like PNG or JPG, ICO files can contain multiple image sizes and color depths within a single file—typically 16x16, 32x32, and 48x48 pixels. This multi-resolution capability allows operating systems and browsers to automatically select the most appropriate size for different display contexts. While ICO files were initially designed for desktop applications and folder icons, they've become the de facto standard for website favicons—those small icons that appear in browser tabs, bookmarks, and address bars. Modern ICO files can support full 32-bit color with transparency, making them versatile enough for today's high-resolution displays.

While modern browsers support PNG favicons, ICO files remain the most universally compatible choice for website icons. Older browsers, particularly legacy versions of Internet Explorer, only recognize ICO format for favicons. More importantly, ICO files' ability to package multiple resolutions ensures your favicon looks crisp across different contexts—from browser tabs to bookmark menus to Windows desktop shortcuts. When users save your website to their desktop or pin it to their taskbar, the ICO file provides the operating system with appropriately sized icons automatically. This eliminates the pixelation or blurriness that can occur when a single-resolution image is scaled up or down. For maximum reach and professional presentation, ICO format gives you the broadest compatibility with the least amount of technical overhead.

A great favicon is simple, recognizable, and works at tiny sizes. Start with a square PNG image at least 256x256 pixels—this gives you enough detail to scale down cleanly. Focus on bold shapes and high contrast rather than intricate details, since your icon will often display at just 16x16 or 32x32 pixels. Avoid text unless it's a single letter or simple logo mark, as fine typography becomes illegible at small sizes. Use solid backgrounds or ensure transparency is intentional, since favicons appear against various browser themes and backgrounds. Once you've designed your icon, convert it to ICO format to include multiple resolutions in one file. Test your favicon in different browsers and contexts—browser tabs, bookmarks, and mobile home screens—to ensure it remains clear and recognizable at every size.