Convert ICO to AVIF
Convert ICO images to AVIF free, in your browser. No upload, no account, no watermark.
Runs in your browser. Nothing is uploaded.Change the format. Drop an image, a PDF or a Word document.
- JPG · PNG · WebP · Text · Word
- Word
- PDF · Text
Your files are processed by your own browser and never sent to a server. Open your browser's network tab and convert one, there is no upload to see.
How to convert ICO to AVIF
- Drop your ICO files onto the box above, or paste them with Ctrl+V.
- Pick a quality. Around 90% is indistinguishable from the original for most images.
- Your browser does the work on your own machine.
- Save each file from its tile, or take them all at once.
What changes, and what does not
Detail is thrown away for the first time
ICO keeps every pixel exactly. AVIF does not, and that is the point of it: the file gets far smaller because detail your eye is worst at noticing is discarded. Keep the original if you may need to edit it again.
Colour
ICO: up to 16.7 million with transparency, usually at very small sizes. AVIF: millions, with 10 and 12 bit depth and wide colour where the source has it.
ICO and AVIF side by side
| ICO | AVIF | |
|---|---|---|
| Where it came from | 1985, as the Windows icon format | 2019, built on the AV1 video codec |
| Throws detail away | No, every pixel is kept | Yes |
| Transparency | Yes | Yes |
| Animation | No | Yes |
| Where it opens | Windows and every browser, for favicons | Every current browser. Outside the browser, support is still thin. |
| Best at | Favicons and Windows application icons, holding several sizes in one file | Photographs on a web page you want as small as they can honestly go |
How much smaller will the file be?
Expect a large drop. A photograph saved as ICO carries every pixel exactly, and AVIF does not need to, so falls of eighty or ninety per cent are ordinary. A screenshot or a logo will fall much less, because ICO was already efficient at flat colour and hard edges, and may even grow.
Can I convert it back afterwards?
Not to the same file, no. Going to AVIF discards detail permanently, and converting the result back to ICO gives you a ICO of the damaged picture rather than the original. Keep the original if there is any chance you will need to edit it again.
About ICO
The Windows icon format, usually holding several small sizes in one file.
About AVIF
The smallest of the four, often half a JPG. We ship the encoder, so it costs a one-off download.
Worth knowing: Needs a browser released in the last few years to decode.
Will the quality change?
AVIF is lossy, so the image is decoded and re-encoded and a little detail is dropped. At high quality this is invisible. Convert once from your original rather than repeatedly, because each pass compounds.
Other conversions
ICO also converts to JPG, PNG, WebP, PDF and Word.
AVIF also comes from HEIC, PNG, JPG, WebP and GIF.