AVIF to ICO Converter
Convert AVIF to ICO in your browser. AVIF files usually come from image CDNs, modern web build pipelines and some recent phones; ICO is the better fit for favicons and Windows icons. You get a multi-size ICO with PNG-compressed icons (16, 32, 48 and 256 px by default). Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
AVIF expected · other image formats also work
How to use AVIF to ICO
- 1
Add your AVIF files: drop them here, choose them, or paste from the clipboard.
- 2
Choose the icon sizes to include.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .ico files one at a time or together as a ZIP.
Why use Aback Images for avif to ico
Where the ICO goes next
ICO opens in every browser (as a favicon), Windows and most Linux desktops.
ICO next to AVIF
The ICO keeps the decoded pixels without lossy compression, so expect it to be larger than the AVIF.
No new artefacts
AVIF is already lossy, since it stores lossy or lossless AV1 intra-frame coding; the ICO keeps the decoded pixels losslessly, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
AVIF vs ICO
What changes from AVIF to ICO
Encoding: the AVIF uses lossy or lossless AV1 intra-frame coding; ICO uses each size stored as a headerless BMP or as a complete PNG, and the download is a multi-size ICO with PNG-compressed icons (16, 32, 48 and 256 px by default).
Bit depth: 8, 10 or 12 bits per channel in the AVIF; ICO allows 1 to 32 bits per pixel, set per size, and the ICO written here has 32 bits per pixel. 10 and 12-bit AVIFs, including HDR ones, are decoded to 8 bits per channel.
Colour: YUV 4:4:4 or 4:2:0 with BT.709, Display P3 or BT.2020 primaries, HDR curves possible in the AVIF; ICO supports RGB or a palette, per image, written here as 8-bit sRGB.
Transparency: the AVIF stores it as an auxiliary AV1 image stored beside the colour image; the ICO keeps it as 8-bit alpha in 32-bit and PNG entries, or a 1-bit mask in old icons.
Animation: an AV1 image sequence under the 'avis' brand; the ICO holds one image, so only the first frame is converted.
Metadata: the AVIF can carry EXIF, XMP and ICC stored as HEIF items; ICO can carry only a directory of the sizes inside, with no EXIF, but nothing is copied across.
About AVIF
AVIF uses the AV1 video codec for still images. It is the most efficient widely supported format, often half the size of JPEG, with HDR, wide colour and transparency, but encoding is slow.
An AVIF is a HEIF file, the same ISO base media boxes as MP4, with the brand 'avif'. The picture is an AV1 key frame stored as an image item, and its size, colour and pixel layout are item properties.
AVIF files usually come from image CDNs, modern web build pipelines and some recent phones.
About ICO
ICO is a container that bundles several sizes of the same icon (16, 32, 48, 256 px) into one file. It is still the most compatible format for website favicons and Windows app icons.
An ICO starts with a 6-byte ICONDIR (type 1 for icons) and a 16-byte entry per image giving width, height, colour count and offset. Each image is either a BMP without its file header plus an AND mask, or a complete PNG.
When converting AVIF to ICO makes sense
ICO is the better choice for favicons and Windows icons, while AVIF suits maximum compression on modern websites.
ICO strengths: Multiple sizes in one file; Required by Windows and supported by every browser as a favicon. Drawbacks to weigh: Max 256×256 per image; Not for photos.
Limitations
- Almost any other format needs more bytes than AVIF for the same picture, so expect the file to grow.
- HDR and wide-gamut AVIFs are mapped to standard sRGB on decode, so very bright highlights can look flatter than on an HDR screen.
- Each size inside the ICO is scaled from your image, and detailed artwork loses legibility at 16 and 32 px, so simplify logos first.
- Non-square images are centred on a transparent square for each icon size.
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Frequently asked questions
Does converting AVIF to ICO lose quality?
ICO is written losslessly, so the pixels are stored exactly as decoded. Artefacts already in the AVIF stay, but nothing new is lost. 10 and 12-bit AVIFs, including HDR ones, are decoded to 8 bits per channel.
Is transparency kept in the ICO?
Yes. AVIF stores it as an auxiliary AV1 image stored beside the colour image, and the ICO is written with an alpha channel, so transparent areas stay transparent.
Will my animated AVIF stay animated?
No. ICO holds a single image, so only the first frame is kept. Convert to animated WebP, APNG or GIF to keep the motion, or export every frame with the GIF Frame Extractor.
Which icon sizes are included?
16, 32, 48 and 256 px by default, the set Windows and browsers expect. You can choose other sizes. Non-square images are centred on a transparent square.
Which apps open ICO files?
Every browser (as a favicon), Windows and most Linux desktops.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.