At One Place

.ico files

.ico file
Windows Icon
A container holding one icon at several sizes, used by Windows and by website favicons.

What opens a .ico file

Windows
Photos (built in), IrfanView, GIMP, Paint (built in — single size only)
macOS
Preview (built in), GIMP
Linux
GIMP, Image Viewer / Loupe (built in)
In a browser
Any web browser, favicon.io

What a .ico file is

An ICO file bundles the same icon at multiple resolutions and colour depths so Windows can pick the right one for the desktop, the taskbar or a tooltip. Browsers use the same format for the little favicon in a tab, which is why /favicon.ico still exists on most sites. Windows Photos will display one, but making or editing icons needs a dedicated tool such as GIMP or an online generator.

Converting it

A .ico file is commonly converted to .png, .svg, .icns or .bmp. It is a binary format, so a text editor will show unreadable characters rather than its contents.

Details

Extension
.ico
Full name
Windows Icon
Category
Images
MIME type
image/vnd.microsoft.icon
Created by
Microsoft
Format
Binary

Common questions

How do I open a .ico file?
On Windows use Photos (built in); on macOS use Preview (built in); on Linux use GIMP. A container holding one icon at several sizes, used by Windows and by website favicons.
What is a .ico file?
Windows Icon. An ICO file bundles the same icon at multiple resolutions and colour depths so Windows can pick the right one for the desktop, the taskbar or a tooltip. Browsers use the same format for the little favicon in a tab, which is why /favicon.ico still exists on most sites.
Can I convert a .ico file?
Yes. It is usually converted to .png, .svg, .icns or .bmp, either by exporting from one of the programs listed above or with a format converter.

Related pages

Sources

  1. Media Types Registry — IANA
  2. Official vendor product documentation — At One Place

How these figures are compiled and checked