Convert ICO to AVIF
Output is typically roughly 14× larger.
- Files stay on your device
- Free, no sign-up
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Will converting ICO to AVIF make the file smaller?
Usually, yes. A 12-megapixel photo is around 100 KB as ICO and around 1.4 MB as AVIF — roughly 14× larger. Because AVIF is lossless the result depends entirely on the image content — flat colour and text compress far better than photographic detail.
Does converting ICO to AVIF lose quality?
A little, by design. ICO is lossless and AVIF is lossy, so some detail is discarded in exchange for a much smaller file. At quality 80–90 the result is visually indistinguishable from the original for photographs. For screenshots, logos or anything with sharp text, stay with a lossless format instead — lossy compression creates visible halos around hard edges.
Is transparency preserved when converting ICO to AVIF?
Yes. Both ICO and AVIF support an alpha channel, so transparent and semi-transparent pixels carry across unchanged — a logo with a cut-out background stays cut out, and soft drop shadows keep their gradient rather than picking up a white halo. Because AVIF can compress lossily, a very hard edge against transparency may pick up slight softness at high compression; keep quality at 85 or above for cut-out graphics.
Should I use AVIF or WebP?
AVIF files are typically 25–35% smaller than WebP at the same quality, which is a real win on image-heavy pages. The trade-offs are much slower encoding and a support floor of Safari 16.4 (March 2023), so a small share of visitors cannot see it. Serve AVIF with a WebP fallback via a <picture> element if you want both.
How it works, and more about ico to avif
How it works
- Add your ICO file. Drag a ICO file onto the drop zone, or click to browse. You can select several at once.
- Choose your settings. Adjust the quality slider if you want a smaller file or a sharper result. 80 suits most photographs.
- Download the AVIF. Conversion runs on your device as soon as each file is added — no upload, no queue. Download each result when it is ready.
ICO and AVIF side by side
| ICO | AVIF | |
|---|---|---|
| Full name | Windows Icon | AV1 Image File Format |
| Compression | Lossless | Lossy or lossless |
| Transparency | Yes — alpha channel | Yes — alpha channel |
| Animation | No | Yes, in the format |
| Browser support | Universal for favicons | Chrome 85+, Firefox 93+, Safari 16.4+ (March 2023), Edge 121+ |
| Typical 12 MP photo | ~100 KB | ~1.4 MB |
| Usually used for | Website favicons and Windows application icons | Performance-critical web images where every kilobyte counts |
On a typical 12-megapixel phone photo, the AVIF output comes out roughly 14× larger than the ICO original. These are order-of-magnitude figures for one kind of image — your own results will vary a great deal, because flat colour, text and line art behave nothing like photographic detail, and the quality slider moves the figure substantially.
What this tool actually produces
Not estimates. Each row below was produced by running the file through this page in a real browser and measuring the result, at the default quality of 82.
| Test image | ICO in | AVIF out | Change |
|---|---|---|---|
| Logo with transparency 512 × 512, flat colour on a transparent background | 264 KB | 3 KB | -99% |
Every test image got smaller, though by very different margins — flat colour and text behave nothing like photographic detail, so treat the closest row to your own content as the useful one. Measured in Chrome 150.0.7871.46; other browsers encode slightly differently.
What to watch out for
- Encoding is computationally expensive and noticeably slow
- Requires Safari 16.4+ (2023), so a small share of users still miss it
- Sparse support outside browsers — most desktop editors cannot open it
About the two formats
ICO is a container rather than a codec: it bundles the same icon at several sizes — typically 16, 32, 48 and 256 pixels — so the operating system or browser can pick the right one. Its remaining job is the favicon at the root of a website, and Windows application icons.
AVIF currently produces the smallest files of any widely supported format — commonly half the size of JPEG at the same perceived quality, with excellent handling of gradients and noise. The cost is encoding time, which can be seconds per image rather than milliseconds, and support that only became universal with Safari 16.4 in 2023.
Other conversions
Everything runs on your device — nothing is uploaded, so there is no size limit, no queue and no copy left on a server afterwards. There is more on how browser-based conversion works if you want the detail. Otherwise, browse every image tool, or convert AVIF back to ICO.