ICO to AVIF Converter
Most people never need an icon in AVIF, but if you are testing formats or building an image set for a modern site, it is a fair question. This page reads an ICO in your browser and writes an AVIF, keeping transparency. It only works when your browser is able to encode AVIF.
How to convert ICO to AVIF
- Add your ICO files by dropping them, clicking the drop zone or pasting.
- The output format is already set to AVIF. Adjust quality or size if you need to.
- Press Convert and compare the original and new size for each file.
- Download each file or all of them as a ZIP.
When to convert, and when not to
- You are comparing image formats on a small graphic.
- You maintain a modern site and want every asset in a consistent next-generation format.
- You can provide a PNG or WebP alternative for older software.
- Skip it if the result must be a favicon or open on older systems; AVIF is the wrong tool for that.
What changes
- The AVIF option is enabled only if your browser can write AVIF. A greyed-out button means it cannot.
- The converted picture is the image the browser shows from the ICO, normally the largest or default entry.
- Transparency is kept because AVIF supports it.
- Compression is lossy and controlled by the quality slider.
- For tiny graphics, the encoder overhead may mean little or no benefit, so compare the sizes shown with a PNG of the same icon.
When AVIF is a poor fit for an icon
AVIF shines on photographs and larger images, where its modern compression can save a lot of data. An icon is a handful of pixels. There is little to compress, and the file can end up about the same size as a PNG or even larger. The honest approach is to convert a few of your icons, read the sizes and decide whether the extra complexity is worth it.
What your browser must support
Writing AVIF is a bigger task for a browser than reading it. Some browsers can display AVIF but cannot create it from a canvas. This page tests that ability before enabling the button, so you never end up with a mislabelled file. If AVIF is disabled for you, WebP or PNG are the practical alternatives.
Reading the source ICO is a separate step handled by the browser too. If it cannot read your icon, you will see an error message for that file.
Keeping a safe master copy
Because AVIF and the ICO are both ways of packaging the same small picture, store a lossless PNG as your master. You can always create new ICO, WebP or AVIF versions from it without compounding quality loss.
Treat this conversion mainly as an experiment or a way to standardise a folder of assets. For icons themselves, PNG or an inline vector is often the simpler and smaller option, which you can confirm by converting the same icon both ways and reading the sizes.
If AVIF output is available in your browser and you decide to use it, always keep the original ICO. Lossy AVIF files are not a good master copy, and a lossless original lets you generate other formats later without compounding any loss.
Privacy: your files stay on your device
- The tool decodes, resizes and encodes your pictures with your browser. The files are never sent to a server.
- To check it yourself: open the browser developer tools (F12), open the Network tab, convert a file, and look for any request that carries your image. You will see none.
Frequently asked questions
Why is the AVIF button disabled?
Your browser cannot encode AVIF. Try a different current browser or choose WebP or PNG.
Will the AVIF be smaller than the ICO?
Not necessarily. Icons are tiny, so compare real sizes before deciding.
Is transparency preserved?
Yes, AVIF can store it.
Which size does it use from a multi-size icon?
The image your browser shows, usually the largest or default entry.
Does this upload my file?
No. Reading and encoding both happen in your browser.