How to Convert AVIF to ICO: Step-by-Step Tutorial

By Bill Crawford  ·  March 2026  ·  6 min read  ·  Last updated March 7, 2026

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What This Tutorial Covers

This tutorial walks you through converting AVIF images to ICO format using the browser-based tool on this site. No software installation required. You will learn how to add files, understand the per-file status system, use batch ZIP download, and deploy your ICO as a favicon.

For background on why you might want ICO and when to use it, see the companion AVIF to ICO Complete Guide.

What You Need

• One or more .avif files (logos, icons, graphics, or images in AVIF format)
• A modern browser: Chrome 85+, Firefox 93+, Edge 121+, or Safari 16.4+
• No account, no software, no subscription

Note: Unlike HEIC conversion, AVIF is decoded natively by modern browsers. No third-party library is required, which makes conversion faster and more reliable.

Step 1: Open the Converter

Navigate to dataconversioncenter.com/image-tools/avif-to-ico/. The page loads with only JSZip from CDN — no other external libraries are needed because AVIF decoding is handled natively by your browser. The ICO encoder is written in pure JavaScript and runs entirely in your browser.

Step 2: Add Your AVIF Files

You have two ways to add files:

• Drag and drop: Open your file manager and drag one or more .avif files directly onto the drop zone labeled "Drop AVIF files here". The zone highlights in blue when you hover over it.
• Browse: Click anywhere on the drop zone (or the "Browse Files" link) to open your file picker. Select multiple files using Ctrl+click (Windows) or Cmd+click (Mac).

As soon as files are added, the tool generates thumbnail previews for each one using the browser's native AVIF decoder. You will see an Input Files grid with a card per file showing the filename, file size, and a Ready status badge.

Note: Files with an extension other than .avif are automatically rejected with an inline error message. They are not added to the conversion queue.

Step 3: Choose Download Mode

Before converting, decide how you want to download your ICO files:

• Individual downloads (default): Leave "Download as ZIP" unchecked. After conversion, each output card has its own Download button, and a "Download All ICOs" button appears for sequential bulk download.
• ZIP archive: Check "Download as ZIP". After conversion, a single "Download ZIP" button downloads all ICOs in one file named dataconversioncenter_avif_to_ico_YYYYMMDDHHMM.zip using your local date and time.

For batches of more than 5 files, the ZIP option is strongly recommended to avoid multiple browser download dialogs.

Step 4: Click "Convert to ICO"

Click the blue Convert to ICO button. The button label changes to "Converting…" and is disabled while conversion runs.

For each file in sequence:

1. The status badge on the input card changes from Ready to Converting…
2. The browser's native createImageBitmap() API decodes the AVIF to pixel data in memory.
3. The pixel data is drawn to an HTML Canvas element at full source resolution.
4. The canvas is scaled to six sizes: 16, 32, 48, 64, 128, and 256 pixels square.
5. Each scaled canvas is encoded as a PNG blob.
6. All six PNG blobs are assembled into a standards-compliant ICO binary with a proper ICONDIR header and ICONDIRENTRY table.
7. The status changes to Converted and an output card appears.

The progress bar tracks overall progress — "Converted X of N". Files are processed two at a time for throughput efficiency.

Step 5: Review the Results

After conversion completes, a summary banner appears: "✓ All N files converted successfully" or "Completed: X succeeded, Y failed."

An Output Files grid displays cards for each successfully converted ICO, showing:

• A thumbnail preview (the full-resolution source rendered for display)
• The output filename — same base name as the input with .ico extension (e.g. logo.avif → logo.ico)
• Output file size (typically 50–300 KB for a 6-size ICO)
• A per-file Download ICO button

Any files that failed to convert are marked with a red Error badge. The most common cause is an outdated browser that does not support AVIF decoding. Update to Chrome 85+, Firefox 93+, Edge 121+, or Safari 16.4+ to resolve this.

Step 6: Download Your ICOs

Individual download

Click the ⬇ Download ICO button on any output card to save that file. The filename is the same as the input with .ico extension.

Download All (no ZIP)

With "Download as ZIP" unchecked, click Download All ICOs. The tool triggers sequential browser downloads with a 120 ms delay between each to prevent browser throttling.

Download ZIP

With "Download as ZIP" checked, click Download ZIP. JSZip assembles all ICO blobs in memory and downloads a single file named, for example, dataconversioncenter_avif_to_ico_202603071430.zip.

Step 7: The Tool Resets Automatically

After a ZIP download or "Download All" completes, the tool automatically resets to its initial empty state. All thumbnails, cards, and file references are cleared. The checkbox resets to unchecked. This prevents accidental re-downloads and keeps browser memory clean between sessions. Click Start Over to reset manually at any point.

Bonus: Deploy as a Favicon

If your goal is a website favicon, here is what to do after downloading the ICO:

1. Rename the file to favicon.ico.
2. Upload it to the root directory of your web server (the same level as index.html).
3. Add this to your HTML <head>: <link rel="icon" href="/favicon.ico" sizes="48x48">
4. Clear your browser cache and reload — the new favicon should appear in the browser tab.

For high-DPI displays, also add an SVG or 32×32 PNG favicon alongside the ICO for the sharpest rendering on Retina screens.

Troubleshooting

• File shows Error status: Your browser may not support AVIF decoding. Update to Chrome 85+, Firefox 93+, Edge 121+, or Safari 16.4+. Also verify the file has a genuine .avif extension and is not a renamed image in another format.
• Thumbnails not generating: Very large AVIF files may take a few seconds to decode the preview. The tool will proceed when ready.
• ICO looks blurry at 16px: The source image has too much fine detail for small sizes. Use a simpler, higher-contrast source image with a bold centered subject — typical of logos and icons.
• ZIP not downloading: Some browsers require a direct user interaction to trigger downloads. Ensure you clicked the Download ZIP button directly rather than via a script.
• Transparency not preserved: This should not occur as AVIF transparency is decoded correctly by all supported browsers. If you see a black or white background where transparency was expected, check that the source AVIF genuinely contains an alpha channel.

Next Steps After Conversion

• Deploy as favicon: Follow the steps above to place favicon.ico in your web root.
• Use in Windows app: Add the ICO file to your Visual Studio or other IDE project as an application icon resource.
• Convert to TIFF for print: Use AVIF to TIFF if you also need a high-resolution print or archival version of the same source.
• Resize for other targets: Use Image Resizer to scale the source to specific social media or app store icon dimensions.
• Convert other formats to ICO: If you also need ICO from HEIC, BMP, or TIFF sources, try HEIC to ICO or BMP to ICO.

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