An ICO is a box of icons, the AVIF is one picture
A Windows ICO file can hold the same icon at several sizes, usually 16, 32, 48 and 256 pixels, each stored as bitmap or PNG data. Windows picks the size it needs. That is useful for a desktop or a favicon and useless when you want the artwork itself, for example to show an app icon in a blog post, a README or a slide.
This converter writes one AVIF per ICO. There's no size picker, so open the output and check its pixel size before you use it. A 256-pixel icon scales down cleanly; a 16-pixel one looks soft if you enlarge it. The AVIF displays in Chrome 85, Firefox 93 and Edge 121 or later, and in Safari on iPhone from iOS 16 and Safari 16.4 on Mac.
How to convert ICO to AVIF
- Upload the .ico files, up to 5 per batch. The 300 MB cap per file is far beyond any icon.
- Set AVIF as the output.
- Download the .avif. Icon files are tiny, so the result is ready almost at once.
The conversion runs on our servers.
Keep the ICO for the favicon
If the icon is your site's favicon, leave the .ico in place. Every browser reads favicon.ico and it already holds the small sizes a tab needs. Convert to AVIF only for the copy you place inside a page. To build an icon from an AVIF, use AVIF to ICO. Other targets for icon files are on the ICO converter page.