AVIF to ICO

What is AVIF?

AVIF (AV1 Image File Format) is a modern raster image format released in 2019 by the Alliance for Open Media, the same industry consortium behind the AV1 video codec. Built on AV1's intra-frame coding technology, AVIF achieves exceptional compression efficiency — typically producing files about 50% smaller than JPG at equivalent visual quality. AVIF supports both lossy and lossless compression, wide colour gamut, HDR (high dynamic range), 12-bit colour depth, and alpha-channel transparency, making it one of the most technically capable image formats available today.

Because of these strengths, AVIF has been adopted by Netflix, Google Images, Cloudflare, WordPress and many other major platforms as a next-generation web image format. However, AVIF is still relatively new: decoding requires a modern browser (Chrome 85+, Firefox 93+, Safari 16+), and many older applications, content management systems, image editors and email clients cannot open .avif files at all. For favicon use, AVIF's tiny file size is a genuine advantage — but only if you can convert it into the universally-recognised .ico container that browsers and bookmarking tools request.

What is ICO?

ICO is the historical icon container format introduced by Microsoft in 1985 for the Windows 1.0 operating system. An .ico file is not a single image format — it is a small container that can hold one or more bitmaps or PNG-compressed images at different sizes (typically 16×16, 32×32, 48×48, 64×64, 128×128, and 256×256) and color depths. Browsers, the Windows shell, bookmark managers, and desktop shortcuts all look for an .ico file (commonly favicon.ico) at the root of a website to display the site's icon in tabs, history lists, the address bar, and the desktop.

Although modern browsers can also use PNG, SVG, and WebP favicons via the <link rel="icon"> tag, the .ico format remains the most universally recognised favicon container. Older browsers and many third-party tools (bookmark managers, feed readers, RSS clients, desktop link generators) still request /favicon.ico by default, so placing a real .ico file at that URL is the safest way to guarantee every visitor sees your icon. This tool produces a single-size .ico file containing a PNG-compressed image at the size you choose.

AVIF vs ICO comparison

AVIF and ICO are built for fundamentally different purposes: AVIF is a modern raster format engineered for photographic compression, while ICO is a legacy container designed specifically for icons and favicons. The table below summarises the key differences between the AVIF and ICO formats.

Feature	AVIF	ICO
Image type	Raster (pixel-based)	Raster container (pixels)
Year introduced	2019	1985
Compression	AV1 (lossy/lossless)	Embedded BMP or PNG
Best for	Photographs, complex raster images	Favicons, app icons, shortcuts
Transparency	Yes (alpha channel)	Yes (via embedded PNG)
Animation	Yes (image sequences)	No (static container)
Browser support	Modern browsers only	All browsers (legacy favicon format)
Default request URL	—	/favicon.ico

In short, AVIF wins on compression and modern feature set, while ICO wins on legacy favicon compatibility. Converting an AVIF image to an .ico file produces a fixed-resolution pixel image that is recognised by every browser, bookmarking tool, and desktop shortcut generator — including the legacy ones that still look for /favicon.ico.

When to use AVIF to ICO conversion

Although AVIF is an excellent format for photographs and complex web imagery, there are many real-world situations where converting it to an .ico favicon is the better choice. Whenever a platform, service, or workflow expects a real .ico file rather than a modern raster format, converting AVIF to ICO gives you the best of both worlds — the source quality of AVIF and the broad compatibility of ICO:

• Launching a new website. Placing a real favicon.ico at the site root ensures every browser — including older ones that ignore <link rel="icon"> tags — shows your icon in the tab.
• Legacy tool compatibility. Bookmark managers, RSS readers, and desktop link generators still request /favicon.ico directly. An AVIF file cannot satisfy that request, but an .ico file can.
• Desktop shortcuts. When a user drags a URL to the desktop, Windows and many Linux file managers pull the icon from favicon.ico, so a real .ico file is required for a crisp shortcut.
• Progressive Web Apps. A PWA's manifest.json can reference .ico files for legacy install contexts and older Android and Windows shell integration.
• Older browsers. Visitors using older browsers that cannot decode AVIF will still see your favicon, because .ico is supported universally.
• Brand consistency. Distributing a single .ico file across web, desktop, and bookmark channels keeps your icon identical everywhere, even when your master is AVIF.

Keep your source AVIF as the master — it is small and high quality. Use the .ico export when you need a compact, fixed-size favicon for deployment scenarios where ICO is still the expected format.

How to convert AVIF to ICO

Converting an AVIF image to an .ico favicon with this tool takes only a few seconds and happens entirely inside your browser. No upload, no sign-up, and no installation are required. The tool loads your AVIF via the browser's native image decoder, draws it onto a square canvas at the size you choose (preserving aspect ratio and centring on a white background), and then re-encodes the canvas into an .ico container via the Canvas API. Follow these four steps:

1. Upload your AVIF file. Click the upload area or drag and drop a .avif file from your computer. The image is decoded locally and shown as a preview.
2. Choose the ICO size. Pick one of 16, 32, 48, 64, 128 or 256 px. 32×32 is the standard favicon size; 16×16 is the classic tab icon; 48×48 and larger are used by high-DPI displays and desktop shortcuts.
3. Convert to ICO. Click the "Convert to ICO" button. The tool rasterizes the AVIF onto a square canvas at the chosen size and wraps the PNG bytes inside a single-image .ico container, showing the original and converted file sizes side by side.
4. Download the ICO. Click "Download ICO" to save favicon.ico to your device. Upload it to the root of your website or drop it into your project's assets folder.

Because every step runs locally in your browser using JavaScript, your AVIF image is never uploaded to a server. This makes the conversion completely private, fast, and suitable for sensitive brand assets.