Convert ICO to AVIF
Convert an ICO into an AVIF right here on the page. ICO is the icon file that Windows and browsers use, and it holds several sizes of the same picture in one file so nothing ever has to be stretched. Your file never leaves your computer.
Need the other direction? Convert AVIF to ICO
How to convert ICO to AVIF
- 1 Drop your ICO .ico file onto the page, or click to browse for it.
- 2 Set the quality, or leave the default, which keeps the file small without anything showing.
- 3 Convert. The work happens on your own machine, so how long it takes depends on your computer and the file.
- 4 Download the AVIF, or add more files and do the whole set in one go.
Why convert ICO to AVIF
- Best size-to-quality ratio of any widely supported still format.
- Handles transparency and very bright, very colourful photographs.
- Hero images and photography where bandwidth is the bottleneck.
- ICO: older BMP-based entries waste a lot of space.
ICO compared with AVIF
How the two formats differ on the things that decide whether a conversion is worth making.
| Property | ICO | AVIF |
|---|---|---|
| File extension | .ico | .avif |
| Animation | No | Yes |
| Multiple pages | Yes | No |
| Colour depth | Up to 32-bit with alpha | Up to 12 bits per channel, HDR and wide gamut |
| Browser support | Every browser | All current browsers |
| Introduced | 1985 | 2019 |
| Developed by | Microsoft | Alliance for Open Media |
| Standard | Proprietary | Open |
Quality and what changes
AVIF stores the same content under a different set of rules, so what matters here is compatibility rather than picture quality. Convert once from the best source you have rather than through a chain of intermediate files.
- A multi-page ICO produces one AVIF per page.
- One AVIF limitation to keep in mind: pushed too hard it smears fine texture rather than showing blocks.
Questions about ICO to AVIF
What happens to a multi-page ICO?
AVIF holds one page, so each page becomes a separate file and you get the set as a ZIP. Nothing is discarded, it just cannot stay in a single document.
Is my ICO file uploaded anywhere?
No. The whole thing runs inside the browser tab you already have open. Your ICO is read straight from your own disk, converted on your machine and handed back as an AVIF. Nothing is sent anywhere, nothing is stored and there is no account.
Is there a file size limit?
There is no server-side limit because no server sees the file. The real ceiling is your device memory, since the input and the output both have to fit in the tab. A few hundred megabytes is usually fine on a desktop machine and considerably less on a phone.
Can I convert several ICO files at once?
Yes. Add as many as you like and they are processed one after another, then offered as separate AVIF downloads or as a single ZIP. Speed depends on your own processor rather than on a queue.
Does the converter work offline?
Yes, after the page has loaded once. The engine is cached by the browser, so you can disconnect, reload and keep converting. That falls out of doing the work locally rather than being a separate mode you switch on.