ICO to PNG Converter — Extract Favicon Icons Online Free

This icon extraction tool parses the ICO (Windows Icon) file format and converts each contained image into standard PNG files for universal compatibility. ICO files use a binary structure starting with an ICONDIR header specifying the number of contained images, followed by ICONDIRENTRY records that describe each icon's dimensions, color depth, and data offset within the file.

The parser reads each directory entry to determine whether the embedded image data is in BMP (Device Independent Bitmap) or PNG format. Modern ICO files often embed PNG-compressed images for sizes 256x256 and above, while smaller sizes typically use the older BMP format with optional alpha channel transparency. For BMP entries, the tool strips the ICO-specific header adjustments, reconstructs proper bitmap data, renders it onto an HTML5 Canvas element, and exports as PNG. For embedded PNG entries, the data is extracted directly without re-encoding.

Multi-resolution ICO files commonly bundle several sizes (16x16, 32x32, 48x48, 256x256) within a single container. The converter displays all extracted sizes with individual download buttons, allowing users to select exactly the resolution they need. Processing occurs entirely client-side through JavaScript typed arrays, guaranteeing privacy for proprietary icon assets.