How do I convert ICO to AVIF?

Add your ICO file to the upload area above, then press Convert. The AVIF file downloads straight to your device. You do not need an account, and there is no watermark.

Are my files uploaded to a server?

No. This conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can even disconnect from the internet after the page loads and it will still work.

Does converting to AVIF reduce quality?

AVIF uses lossy compression, so some data is discarded. At the default quality the difference is very hard to see or hear; raise the quality setting if you need to be certain, at the cost of a larger file.

How large a file can I convert?

Up to 120 MB per file for this conversion. Because the work happens in your browser, the practical limit is your device's memory — larger files work on a desktop with plenty of RAM and may fail on an older phone.

Can I convert several files at once?

Yes. Add as many as you like and press Convert All. Each file is processed independently, so one failure does not stop the rest, and you can download everything together as a ZIP.

Can I use this on my phone?

Yes. FileTools360 works in mobile browsers on iOS and Android, including choosing files straight from your camera roll. Very large videos may run out of memory on a phone — those are better converted on a laptop.

ImageAdjustable qualityRuns in your browser

ICO to AVIF Converter

Turn ICO files into AVIF in a couple of clicks. Multi-resolution icon container for favicons and apps. Next-gen format with the best compression available today. The output is re-encoded, so quality depends on the settings you choose.

On your deviceNever uploadedGone when you close the tabHow this works

Drop your files here

ICO files (.ico) · up to 120 MB each

or paste files from your clipboard

Ready when you are

Drop a ICO file above and FileTools360 will turn it into AVIF — right here on your device, without uploading anything.

⌘K to search converters

How to use it

1
Add your ICO files
Drag them onto the upload area, choose them from your device, or paste them from your clipboard. You can queue several at once.
2
Adjust the settings if you want to
The defaults suit most people. Open Advanced to control quality, dimensions, rotation and metadata removal.
3
Convert and download
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.

ICO and AVIF explained

ICO is a container that holds several versions of the same icon at different sizes, so the operating system or browser can pick the one that fits. It is capped at 256×256 pixels.

AVIF stores still images using the AV1 video codec's intra-frame compression. It generally achieves the smallest files of any widely supported format, and it handles wide colour gamut and HDR, which JPEG cannot.

Where ICO files come from: Website favicons and Windows application icons.
Where AVIF is used: Performance-focused websites and modern image pipelines.

ICO vs AVIF

The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.

ICO compared with AVIF
Property	Source	Target
Compression	Lossy or lossless	Lossy or lossless
Transparency	Yes	Yes
Animation	No	Yes
Introduced	1985	2019
Browser support	Browsers and Windows. Sizes are capped at 256×256.	Modern browsers only. Limited desktop app support.

ICO is stronger at: Holds multiple resolutions in one file. The format browsers expect for favicon.ico. Supports transparency.
AVIF is stronger at: The best compression of any broadly supported image format. Handles HDR and wide colour gamut. Supports transparency and animation.

Why convert ICO to AVIF?

People make this switch when they run into the limits of ICO: anything else. AVIF is the better fit when you control the audience (a modern website) and file size is the priority.

ICO limitations that prompt the switch: Capped at 256×256. Not a general-purpose image format. Awkward to edit.
What you give up: Encoding is slow compared with JPEG or WebP. Desktop application support is still thin.

Does converting ICO to AVIF reduce quality?

Both formats store the content without discarding data, so this conversion preserves it exactly. The file size may change because the two formats compress differently, but the content itself is unaffected.