Convert ICO to AVIF Online — Free & Private
Converting ICO to AVIF re-encodes an image from Windows Icon into AV1 Image File Format. This free converter does it entirely inside your browser — your files are never uploaded — and handles unlimited batches with no sign-up, no watermark and no software to install.
Drag & drop your ICO files here
Batch conversion supported · up to 50 MB per file
🔒 Processed locally in your browser — nothing is uploaded.
How to convert ICO to AVIF
To convert ICO to AVIF: add your files to the converter above, confirm AVIF is selected as the output format, press Convert, then download the result. The whole process runs in your browser and takes a few seconds.
- Add your files. Drag ICO files onto the box above, or click Choose files to browse. Multiple files at once are fine — there is no limit on how many.
- Check the settings. AVIF is already selected. Adjust the quality slider if you want a smaller file or a more faithful one; 85% suits most images. Turn on Resize output if you need specific dimensions.
- Press Convert. Each file is decoded, redrawn and re-encoded on your device, with progress shown per file.
- Download. Take files individually, or use Download all as ZIP for the whole batch.
Why convert ICO to AVIF?
Converting ICO to AVIF usually comes down to compatibility or file size. Squeezing web images as small as they will go, when you can serve a fallback to older browsers.
ICO vs AVIF: what actually changes?
The practical differences are compression, transparency and compatibility. ICO is container with supported at 32-bit colour depth transparency; AVIF is lossy or lossless with full alpha channel transparency. The table below sets out every difference that affects the result.
| Property | ICO | AVIF |
|---|---|---|
| Compression | Container | Lossy or lossless |
| Transparency | Supported at 32-bit colour depth | Full alpha channel |
| Animation | Not supported — the .ani format handles that | Supported |
| Colour depth | Up to 32-bit, including an alpha channel | Up to 12-bit per channel, with HDR and wide colour gamut |
| Introduced | 1985 | 2019 |
| Browser support | Universal for favicons; the original favicon format | Chrome from 2020, Firefox from 2021, Safari from version 16 (2022), Edge from 2023 |
| Typical size | Depends entirely on how many sizes are included | Roughly 0.5× a JPG at matched quality |
| Best for | Website favicons and Windows application icons, where several sizes must live in one file. | Squeezing web images as small as they will go, when you can serve a fallback to older browsers. |
What is a ICO file?
ICO stands for Windows Icon. Introduced in 1985 by Microsoft, it uses container compression and is best suited to website favicons and Windows application icons, where several sizes must live in one file.
The Windows and favicon format. Holds several square sizes in one file; 16×16, 32×32 and 48×48 are the sizes browsers actually reach for.
| Property | ICO |
|---|---|
| Full name | Windows Icon |
| File extensions | .ico |
| MIME type | image/x-icon |
| Introduced | 1985 |
| Developed by | Microsoft |
| Compression | Container |
| Colour depth | Up to 32-bit, including an alpha channel |
| Transparency | Supported at 32-bit colour depth |
| Animation | Not supported — the .ani format handles that |
| Browser support | Universal for favicons; the original favicon format |
| Typical file size | Depends entirely on how many sizes are included |
ICO strengths
- Stores multiple resolutions in a single file
- The most broadly compatible favicon format, including very old browsers
- Alpha transparency for non-square icon shapes
ICO limitations
- Restricted to icon-sized square images
- No use outside icons
- Larger than a single equivalent PNG, since it holds several copies
What is a AVIF file?
AVIF stands for AV1 Image File Format. Introduced in 2019 by Alliance for Open Media (Google, Netflix, Mozilla, Amazon and others), it uses lossy or lossless compression and is best suited to squeezing web images as small as they will go, when you can serve a fallback to older browsers.
The AV1-based successor to WebP. Best-in-class compression — often half the size of JPG — with wide, modern browser support.
| Property | AVIF |
|---|---|
| Full name | AV1 Image File Format |
| File extensions | .avif |
| MIME type | image/avif |
| Introduced | 2019 |
| Developed by | Alliance for Open Media (Google, Netflix, Mozilla, Amazon and others) |
| Compression | Lossy or lossless |
| Colour depth | Up to 12-bit per channel, with HDR and wide colour gamut |
| Transparency | Full alpha channel |
| Animation | Supported |
| Browser support | Chrome from 2020, Firefox from 2021, Safari from version 16 (2022), Edge from 2023 |
| Typical file size | Roughly 0.5× a JPG at matched quality |
AVIF strengths
- Often half the size of JPG at the same visual quality
- Royalty-free, unlike HEIC
- HDR, wide gamut, alpha and animation in one format
AVIF limitations
- Encoding is computationally expensive and can be slow
- Desktop image editors still lag on support
- Older browsers and devices need a fallback
Does converting ICO to AVIF lose quality?
Yes, slightly — AVIF is a lossy format, so some detail is discarded during encoding. At the default 85% quality the difference is invisible to the eye for most images. Raise the slider toward 100% when archiving, or lower it when the smallest file matters most.
Two distinct things are often confused here. The first is whether the target format discards data: AVIF is lossy or lossless, so it does, in a controlled amount you set with the quality slider. The second is whether the source already lost data: ICO is container, so the source holds the original detail intact.
A practical rule: converting repeatedly between lossy formats compounds the damage each time. If you expect to edit an image more than once, work in a lossless format and export to a lossy one only at the end.
Is it safe to convert ICO files here?
Yes, and you can verify it rather than trust it. Your ICO file is read, decoded and re-encoded inside your browser tab. There is no upload endpoint on our side, so no copy of your image exists anywhere but your own device.
Most online converters upload your file to a server, process it there and promise to delete it later. That promise is unverifiable, and it does not survive a breach, a misconfigured storage bucket or a legal request. This tool removes the question entirely: the code comes to you, the file stays put.
To confirm it for yourself, open your browser’s developer tools, switch to the Network tab, and convert a file. You will see the page assets load and nothing carrying your image leave. It also works with your connection switched off entirely, once the page has loaded.
ICO and AVIF at a glance
ICO files use the image/x-icon MIME type and the .ico extension; AVIF files use image/avif and .avif. The summary below covers the properties that matter when choosing between them.
| ICO | AVIF | |
|---|---|---|
| Full name | Windows Icon | AV1 Image File Format |
| Extension | .ico | .avif |
| MIME type | image/x-icon | image/avif |
| Year | 1985 | 2019 |
| Best for | Website favicons and Windows application icons, where several sizes must live in one file. | Squeezing web images as small as they will go, when you can serve a fallback to older browsers. |
ICO to AVIF: frequently asked questions
- How do I convert ICO to AVIF?
- Open this page, drag your ICO files onto the drop zone, and press Convert. AVIF is already selected as the output format. The conversion runs in your browser and finishes in seconds, then you download the result individually or as a ZIP.
- Is this ICO to AVIF converter free?
- Yes, completely. There is no account, no daily limit, no watermark and no paid tier. You can convert as many ICO files as you like, as often as you like.
- Are my ICO files uploaded to a server?
- No. The conversion runs entirely in your browser using the Canvas API and WebAssembly codecs. Nothing about your file is transmitted to us, so there is nothing for us to store, share or lose. You can verify this by opening your browser's Network tab while converting.
- Will converting ICO to AVIF reduce quality?
- AVIF is a lossy format, so some detail is discarded. The quality slider defaults to 85%, which is visually indistinguishable from the original for most images. Raise it toward 100% for archiving, or lower it for the smallest possible file.
- Will the file get bigger or smaller?
- AVIF files are typically roughly 0.5× a jpg at matched quality, against depends entirely on how many sizes are included for ICO. The converter shows the before and after size for every file so you can see the exact result.
- Can I convert multiple ICO files at once?
- Yes. Drop the whole batch in and they convert one after another with individual progress. Download them one by one, or take the entire set as a single ZIP file built in your browser.
- Does AVIF support transparency?
- Yes — full alpha channel. Transparent areas in your ICO file are preserved in the AVIF output.
- Is there a file size limit?
- Each file is capped at 50 MB, because conversion happens in your browser's memory and very large files can crash a tab, particularly on phones. There is no limit on how many files you convert.
- Does it work on iPhone, Android, Mac and Windows?
- Yes. It runs in any modern browser on any operating system — there is nothing to install. Chrome from 2020, Firefox from 2021, Safari from version 16 (2022), Edge from 2023.
- Do I need to install software or sign up?
- Neither. There is no download, no extension, no account and no email address required. Open the page and convert.
Related conversions
Need to go the other way? Try AVIF to ICO. Other conversions involving these formats: