Images · .ico
What Is an ICO File?
A .ico file is an icon format used for Windows program icons and website favicons.
- Extension
- .ico
- Full name
- Windows icon
- Type
- Image
- MIME type
- image/vnd.microsoft.icon
- Developed by
- Microsoft
Free ICO Tools
These run in your browser. Your ICO files are never uploaded.
About ICO Files
An ICO file holds one or more small square images, typically 16, 32, 48 and 256 pixels wide, so Windows and browsers can pick the sharpest size for each place the icon appears. Windows uses ICO files for program and folder icons, and websites have long used a favicon.ico file for the little icon in the browser tab. Each image inside can be stored as a bitmap or as a PNG, with transparency. Modern websites often add PNG or SVG favicons, but favicon.ico is still requested by many browsers and tools.
How to Open an ICO File
- Windows
- Open it in the Photos app
- Mac
- Preview opens ICO files and shows each size inside.
- Any device
- Drag the file into a browser tab to see it.
ICO File Questions
What size should a favicon.ico be?
Include at least 16×16 and 32×32 pixel images; adding 48×48 helps on Windows. Put it at the root of your site as /favicon.ico.
Can I just rename a PNG to .ico?
Most browsers will display it, but Windows won't treat it as a real icon. Convert it properly so the file has the ICO structure.