Convert ICO to AVIF
Free, unlimited ICO to AVIF conversion that runs entirely inside your browser. No upload, no sign-up, no watermark.
Convert your ICO files to AVIF
or drop them here, or paste with Ctrl+V · files never leave your device
Settings
Nothing queued yet. Add as many files as you like — everything runs on your own device.
Nothing is uploaded
Conversion runs in your browser. Your files never touch a server, so there is no copy of them to leak.
No sign-up, no watermark
No account, no email, no daily limit, and nothing stamped across your image.
Batch and folders
Drop a hundred files at once and download the results as a single ZIP.
Works offline
Once this page has loaded you can disconnect entirely and it still works.
This converter turns ICO images into AVIF files without uploading anything. The conversion runs inside this page using your own device's processor, so your photos never leave your computer — there is no server copy to worry about, no queue to wait in, and no limit on how many files you convert.
ICO is the Windows icon container, and the traditional format for a website’s favicon. Universal for its one job: favicons and Windows icons. AVIF, by contrast, all current browsers decode AVIF. Outside the browser, support is still thin — which is usually why you need it converted.
Converting to AVIF is a page-speed exercise: it typically cuts image weight by a third or more with no visible difference, which shows up directly in Core Web Vitals. Keep the original ICO as your master copy and serve the AVIF version.
How to convert ICO to AVIF
- Add your ICO files. Drag them onto the box above, click to browse, or paste an image straight from your clipboard. You can add as many at once as you like.
- Adjust the settings if you need to. The defaults suit most images. Raise the quality slider if the image contains text or flat colour.
- Download the AVIF file. Each file gets its own download button as soon as it finishes, and you can pull the whole batch down as a single ZIP.
What changes when you convert ICO to AVIF
Every format conversion involves trade-offs, and vague tools hide them. Here is exactly what happens to your image in this particular conversion.
- Transparency is preserved: both ICO and AVIF carry a full alpha channel.
- ICO is lossless and AVIF is lossy, so this conversion discards some detail permanently. At the default quality the difference is invisible on photographs, but flat colour, screenshots and text will show faint halos — keep the quality high for those.
- AVIF encoding is genuinely slow — it runs the AV1 compressor in your browser. A large photo can take several seconds. The payoff is a file substantially smaller than the equivalent JPG.
About ICO (Windows Icon)
ICO is the Windows icon container, and the traditional format for a website’s favicon.
Where you probably got it: Website favicons and Windows application icons.
Strengths
- Holds several sizes in one file so each context picks the sharpest
- The one favicon format every browser understands, including very old ones
- Supports transparency
Limitations
- Only useful for icons — sizes are capped at 256x256
- Not a general-purpose image format
- Awkward to create in most image editors
About AVIF (AV1 Image File Format)
AVIF is a modern format built on the AV1 video codec, producing the smallest files of any widely supported image format.
Support: All current browsers decode AVIF. Outside the browser, support is still thin — which is usually why you need it converted.
Strengths
- Typically 30–50% smaller than JPG at visually identical quality
- Handles transparency, HDR and wide colour gamut
- Royalty-free and supported in all current browsers
Limitations
- Encoding is computationally expensive — noticeably slower than JPG or PNG
- Very little support outside browsers: most desktop and print software cannot open it
- Can smear fine texture at aggressive settings
Is it safe to convert ICO online?
Here, yes — and you can check rather than trust. Open your browser’s developer tools, switch to the Network tab and convert a ICO file: no request carrying your image is made. Disconnect from the internet after this page has loaded and the converter still works, which would be impossible if a server were doing the conversion.
That is worth verifying wherever you convert, because most online converters do upload, and ICO files are so often personal photos and documents people would not hand to a stranger. Once a file is on somebody else’s server you are relying on a privacy policy rather than on anything you can observe. We wrote up how to tell a safe converter from a risky one in more detail.
Frequently asked questions
How do I convert ICO to AVIF?
Drag your ICO file onto the box above, or click it to browse. The conversion starts immediately in your browser and the AVIF download appears within a second or two for most images. You can drop in a whole folder of files at once and download them together as a ZIP.
Are my ICO files uploaded to a server?
No. The conversion happens locally in your browser, so your files are never transmitted anywhere — the tool even works with the network disconnected once the page has loaded. That is also why there is no file size or file count limit: nothing costs us anything per conversion. The practical ceiling is your own device's memory, which on a phone means very large images may fail.
Will converting ICO to AVIF reduce the quality?
Slightly, by design. AVIF is a lossy format, so it approximates the image to save space. At the default quality setting the loss is invisible on photographs; on screenshots and text you may see faint halos, so raise the quality slider or choose PNG instead.
What is the difference between ICO and AVIF?
ICO is the Windows icon container, and the traditional format for a website’s favicon. AVIF is a modern format built on the AV1 video codec, producing the smallest files of any widely supported image format. In practice the choice comes down to compatibility: universal for its one job: favicons and Windows icons. Meanwhile all current browsers decode AVIF. Outside the browser, support is still thin — which is usually why you need it converted.