Convert HDR to ICO
Free online HDR to ICO converter. No signup required.
Drag & drop your file here
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Max file size: 100 MB
Why Convert HDR to ICO?
Understand when and why this conversion makes sense for your workflow.
Converting Radiance HDR Image to ICO Image is a common task for web developers, designers, and photographers who need to balance visual quality against file size and compatibility. Different image formats serve different purposes: some prioritize small file sizes for faster page loads, while others preserve lossless quality or support features like transparency. Choosing the right format for your use case can dramatically affect how your images look and how quickly they load across devices and browsers.
Radiance HDR Image has a known limitation: lower precision than 32-bit EXR for demanding visual effects work. In contrast, ICO Image offers a key advantage: can store multiple resolutions and color depths in a single file. While Radiance HDR Image is commonly used for environment maps and image-based lighting in 3d rendering, ICO Image is better suited for website favicons displayed in browser tabs and bookmarks.
Our free online converter handles the HDR-to-ICO conversion in seconds, with no quality loss beyond what the target format inherently requires — no watermarks, no account needed.
HDR vs ICO: Format Comparison
Side-by-side comparison of the source and target formats.
| Property | HDR (Source) | ICO (Target) |
|---|---|---|
| Extension | .hdr | .ico |
| Full Name | Radiance HDR Image | ICO Image |
| Compression | Varies | Varies |
| File Size | Varies | Large |
| Transparency | No | Yes |
| Best For | Environment maps and image-based lighting in … | Website favicons displayed in browser tabs an… |
| Browser Support | Varies | Varies |
How to Convert HDR to ICO
Follow these simple steps to convert your file in seconds.
Upload your HDR image
Drag your .hdr file onto the upload area, or click "Browse" and pick it from your device. Radiance HDR Image files up to 100 MB are accepted, which covers most photos, screenshots, and high-resolution scans. The file is uploaded over HTTPS and is never visible to anyone but you.
Click "Convert to ICO"
Once the upload completes, press the convert button. The image is decoded from Radiance HDR Image, color-managed where the target format requires it, and re-encoded as ICO Image. Default settings produce a sensible balance of quality and file size — no manual encoder tuning is required for typical use.
Wait for the ICO encode to complete
Most image conversions complete in under five seconds. Larger images, batch jobs, or vector files with thousands of paths can take a little longer. The progress bar updates in real time and you can leave the tab open in the background — the conversion runs server-side.
Download your .ico file
When the conversion finishes, click the download link to save the new ICO Image file to your computer. The file is yours — no watermarks, no expiration on the file itself, and no MegaConvert account is required to download it.
Tips for Converting HDR to ICO
Practical advice to get the best results from this conversion.
Why this conversion is worth doing
Radiance HDR Image has a known limitation: lower precision than 32-bit EXR for demanding visual effects work. ICO Image addresses this with a key advantage: can store multiple resolutions and color depths in a single file. Converting from HDR to ICO is most worthwhile when this specific trade-off matters for the way you intend to use the file.
Match the format to the actual workflow
Radiance HDR Image is most commonly used for environment maps and image-based lighting in 3d rendering, while ICO Image is the standard for website favicons displayed in browser tabs and bookmarks. If your workflow is closer to the second pattern, converting makes sense. If you are still working in a context where HDR is the norm, converting may create unnecessary compatibility friction with collaborators or tools that expect the source format.
Watch for this limitation in the ICO output
ICO Image has its own limitation worth understanding before you commit: limited to relatively small image dimensions (max 256x256). After the conversion completes, open the ICO file and verify that this limitation does not affect your specific use case — for some workflows it is irrelevant; for others it can be a deal-breaker.
Choose the right format for your content type
HDR and ICO suit different image types. Lossy formats like JPG work well for photographs with gradual color transitions, while lossless formats like PNG, BMP, and TIFF are better for graphics with sharp edges, text overlays, or flat areas of color. Picking the wrong format can introduce artifacts or unnecessarily inflate file sizes.
Understanding HDR and ICO Formats
Learn about the source and target file formats to understand what happens during conversion.
Source Format
Radiance HDR Image
image/vnd.radianceHDR (High Dynamic Range) Radiance format, also known as RGBE, stores images with a high dynamic range of luminance values using a run-length encoded format. Developed by Greg Ward for the Radiance lighting simulation system, it encodes each pixel as three 8-bit mantissas and a shared 8-bit exponent. HDR images capture a much wider range of brightness than standard 8-bit formats.
Advantages
- Captures a wide dynamic range of lighting from very dark to very bright
- Relatively compact encoding for high dynamic range data
- Widely supported in 3D rendering, game engines, and compositing software
Limitations
- Lower precision than 32-bit EXR for demanding visual effects work
- Not suitable for direct display without tone mapping
- Limited to RGB data with no alpha channel support
Common Uses
- Environment maps and image-based lighting in 3D rendering
- HDR photography merging and tone mapping workflows
- Lighting simulation and architectural visualization
Target Format
ICO Image
image/x-iconICO is an image format used to store icons in Microsoft Windows and for website favicons. A single ICO file can contain multiple images at different sizes and color depths, allowing the operating system or browser to select the most appropriate version. ICO files support sizes from 16x16 up to 256x256 pixels with up to 32-bit color depth including alpha transparency.
Advantages
- Can store multiple resolutions and color depths in a single file
- Universal support as favicons in all web browsers
- Native format for Windows application and system icons
Limitations
- Limited to relatively small image dimensions (max 256x256)
- Larger file sizes than PNG when embedding multiple resolutions
- Primarily Windows-centric with less relevance on other platforms
Common Uses
- Website favicons displayed in browser tabs and bookmarks
- Windows application and shortcut icons
- Desktop and toolbar icons in Windows environments
Frequently Asked Questions
Common questions about converting HDR to ICO.
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