CONVERT AVIF → ICO (AVIF to ICO)
Fast, secure AVIF to ICO conversion. No registration required.
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Lossless JPEG Q100 + standard COM segment padding for government & exam portals
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Automatic format identification and lossless transcoding across 201+ formats.
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EXIF & Color Verification Audit ISO Verified
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GPS Coordinates (37.1773° N, 3.5986° W): Stripped (Zero Location Leak)
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Device Serial & Lens ID: Stripped (EXIF / IPTC / XMP Clean)
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Color Space Profile: Display P3 → sRGB IEC61966-2.1
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Chroma Subsampling: 4:4:4 High Fidelity (High-fidelity algorithmic conversion)
HOW TO CONVERT AVIF → ICO
Upload your AVIF
Start by dropping the AVIF onto the uploader. Files up to 25 MB go through on the free tier without registration; paid plans go up to 2 GB.
Conversion happens server-side
Our imagemagick-based pipeline reads the AVIF pixel grid, preserves resolution and colour profile, and encodes a clean ICO.
Grab the result
A download button appears as soon as the ICO is ready. Save locally or share the short-lived URL.
ICO is a container format that Windows and cross-platform desktop toolchains use to store application and shortcut icons, and it predates modern image codecs by decades. AVIF, by contrast, is a still-image profile of the AV1 video codec, capable of storing HDR content with 10- or 12-bit precision, wide color gamuts such as Display P3 or BT.2020, and lossless or visually transparent compression — properties that are entirely irrelevant to the ICO use case but explain why you ended up with the AVIF in the first place: someone exported a high-fidelity master asset in a modern format and now needs a Windows-compatible icon from it. The conversion path is one-way and lossy in multiple dimensions: ICO internally carries BMP or PNG-compressed frames (the PNG variant has been standard since Windows Vista), each frame must be a square power-of-two resolution, the color space is clamped to sRGB, and bit depth is reduced to 8 bits per channel. Practically every icon pipeline today packages at minimum 16x16, 32x32, 48x48, and 256x256 frames inside a single ICO file so that Windows Explorer, taskbar, and Alt-Tab can select the appropriate resolution without scaling artifacts.
Why convert AVIF to ICO
Desktop application distribution is the overwhelming real-world driver. Windows requires an ICO file to assign an icon to an .exe, a .lnk shortcut, or a folder. Electron apps, Tauri apps, and traditional Win32 or .NET applications all consume ICO at build time. A designer who delivered the icon master in AVIF — because it compresses beautifully and supports the wide gamut needed for marketing assets — now needs to produce a binary-compatible ICO without re-exporting from the original source. Web developers also hit this: browsers still read favicon.ico from the root of a domain as a fallback when no icon link element is present, making ICO the only format with guaranteed legacy browser coverage for favicons.
AVIF vs ICO — Technical specifications
Side-by-side comparison of the technical details.
AVIF
- MIME type
- image/avif
- Container
- HEIF (ISOBMFF)
- Codec
- AV1 (intra-only)
- Max dimensions
- 65 536 × 65 536 px
- Color depth
- Up to 12-bit per channel
- Color spaces
- sRGB, Display-P3, BT.2020, arbitrary ICC
- MIME Type
- image/avif
- Extension
- .avif
- Category
- Raster & Vector Images
- Full Name
- AVIF Image
- Conversion Engine
- IMAGEMAGICK
ICO
- MIME type
- image/vnd.microsoft.icon
- MIME Type
- image/x-icon
- Extension
- .ico
- Category
- Raster & Vector Images
- Full Name
- ICO Icon
- Conversion Engine
- IMAGEMAGICK
- Max resolutions per file
- 65 535 images
- Max single image size
- 256×256 px
- Color depths
- 1, 4, 8, 24, 32 bits per pixel
- Compression
- Uncompressed bitmap or embedded PNG (Vista+)
| Specification | AVIF | ICO |
|---|---|---|
| MIME type | image/avif | image/vnd.microsoft.icon |
| Container | HEIF (ISOBMFF) | — |
| Codec | AV1 (intra-only) | — |
| Max dimensions | 65 536 × 65 536 px | — |
| Color depth | Up to 12-bit per channel | — |
| Color spaces | sRGB, Display-P3, BT.2020, arbitrary ICC | — |
| MIME Type | image/avif | image/x-icon |
| Extension | .avif | .ico |
| Category | Raster & Vector Images | Raster & Vector Images |
| Full Name | AVIF Image | ICO Icon |
| Conversion Engine | IMAGEMAGICK | IMAGEMAGICK |
| Max resolutions per file | — | 65 535 images |
| Max single image size | — | 256×256 px |
| Color depths | — | 1, 4, 8, 24, 32 bits per pixel |
| Compression | — | Uncompressed bitmap or embedded PNG (Vista+) |
AVIF vs ICO — Strengths and limitations
What each format does best, and where it falls short.
AVIF Strengths
- Best-in-class compression efficiency — 30-50% smaller than JPEG for the same quality.
- Royalty-free and patent-unencumbered (unlike HEIC).
- Supports alpha transparency, HDR, wide gamut (BT.2020), and up to 12-bit color.
- Progressive decoding: a blurry preview appears while the file is still downloading.
- Supported in all major browsers since late 2022 — no polyfills needed.
Limitations
- Encoding is CPU-expensive — an AVIF export can take 10-30× longer than JPEG.
- Older software (pre-2022) cannot open AVIF without plugins.
- Email clients still largely ignore it — stick to JPEG for attachments.
ICO Strengths
- Multi-resolution: one file, many sizes, OS picks the right one.
- Universal favicon support in every browser since IE5.
- Supports transparency (1-bit since 1985, full alpha since XP).
- Tiny file size — an entire favicon pack typically fits in under 15 KB.
- No licensing or patent concerns — fully in the public domain spec-wise.
Limitations
- Cannot compress continuous-tone images efficiently — use PNG or WebP for photos.
- Format is essentially frozen in 1999 — no HDR, no wide gamut, no modern features.
- Maximum image dimension is 256×256 px (inside an ICO container).
Quality & Compatibility
AVIF's HDR tonal data and any color gamut beyond sRGB are permanently discarded; the converter maps to sRGB before encoding PNG frames inside the ICO container. If the source AVIF carried an alpha channel, it survives into the PNG-compressed ICO frames, which support full 8-bit alpha — this is the one property that transfers cleanly. AVIF's lossless or near-lossless compression advantage disappears; ICO with internal PNG frames uses standard zlib deflate, which is adequate but not competitive with AV1 entropy coding. AVIF XMP or EXIF metadata is not carried into the ICO format, which has no standardized metadata block. The multi-resolution requirement means the 256x256 frame is the only one that may closely match the original AVIF dimensions; smaller frames are downsampled, so sharp edges in icons benefit from the source AVIF being at least 256x256 to avoid upscaling artifacts.
Tips for Best Results
- Keep the source AVIF at 256x256 or larger before converting — the tool will generate the smaller required frames by downsampling, and starting from a high-resolution source preserves edge sharpness across all ICO frame sizes.
- If your AVIF uses a wide color gamut such as Display P3, check the converted ICO on a standard sRGB display before shipping; saturated oranges and greens in particular can look muted after gamut clipping, and you may need to boost saturation in the source before conversion.
- Verify the resulting ICO contains a PNG-compressed 256x256 frame rather than a BMP-encoded one — Windows Vista and later render the PNG variant at full quality, while old BMP frames at that size show visible dithering on modern high-DPI screens.
Frequently Asked Questions
It depends on the codecs involved. If both AVIF and ICO are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If ICO is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded AVIF exactly, but cannot recover detail that AVIF had already compressed away.
Often yes, especially when ICO is lossless. AVIF tuned for efficient web delivery will usually produce smaller files than ICO's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
AVIF Image
Source formatAVIF is a next-generation image format based on the AV1 video codec. It offers significantly better compression than JPEG and WebP while maintaining excellent visual quality, including HDR and wide color gamut support.
ICO Icon
Target formatICO is the icon file format used for favicons and Windows application icons. A single ICO file can contain multiple image sizes and color depths for different display contexts.
Going the other way? Convert ICO back to AVIF with the same engine.
Common Use Cases
Share across platforms
Send ICO files to anyone without worrying about whether they have the right software for AVIF.
Embed in documents
Drop ICO output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
ICO often produces smaller files than AVIF for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
AVIF vs ICO — Typical file sizes
Approximate file sizes for common scenarios.
- Thumbnail (400px) 10-30 KB
- Web photo (1920px) 80-300 KB
- 4K photo (3840px) 300 KB - 1.2 MB
- Classic favicon (16×16 only) < 2 KB
- Multi-size favicon pack (16/32/48/256) 5-15 KB
- Full Windows app icon set 20-100 KB
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High-throughput enterprise pipeline for files up to 2,048 MB, 50-file batches, ISO PDF/A, and priority processing.
Convert thousands of camera RAW files (CR3, NEF, ARW) to WebP, AVIF, or TIFF in one pass.
GPU-accelerated RAW development with end-to-end 16-bit ICC color profile management.
Related comparisons
See these formats side by side to understand which fits your use case best.
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