What quality should I expect from the HDR output?

Our converter preserves as much fidelity as Radiance HDR Image allows. Where ICO Image carries information that Radiance HDR Image cannot represent, that information is mapped to the closest equivalent (for example, color spaces, codec parameters, or metadata fields). For most everyday uses the result is indistinguishable from the source.

What happens to transparent areas when I convert ICO to HDR?

Radiance HDR Image does not support an alpha channel, so any transparent or partially transparent pixels in your ICO file will be flattened against a solid background — white by default. If you need to keep transparency, convert to a format that supports it (PNG, WebP, AVIF, or TIFF). If you must use HDR, consider compositing the image onto your intended background colour before converting so the result looks correct.

What file size should I expect for the HDR output?

The output size depends on the content and the compression characteristics of Radiance HDR Image. In most cases the HDR file will be in the same ballpark as your ICO input, with differences driven by how each format encodes data. There is no fixed ratio — the converter does not change quality settings unless you ask it to.

When should I convert ICO to HDR instead of staying with ICO?

Convert when the application, device, or workflow you are targeting prefers Radiance HDR Image over ICO Image. If your current ICO file already opens and behaves correctly everywhere you need it to, there is no benefit to converting — keep the original. The most common reasons to switch are compatibility (a tool only accepts HDR), distribution (recipients expect HDR), or feature requirements specific to Radiance HDR Image.

What is the maximum ICO file size I can convert?

MegaConvert accepts ICO files up to 100 MB on the free service, which is enough for the vast majority of real-world ICO Image files. If you have a larger file (typical for high-resolution video or uncompressed audio), please contact us — we can sometimes accommodate larger uploads for legitimate use cases.

Is my ICO file safe and private when I upload it?

Yes. Your ICO file is uploaded over HTTPS, processed in an isolated job environment, and deleted from our servers within one hour. We do not read, index, store, or share the contents of your file. No account is required, so the upload is not associated with a personal identity. See our privacy policy for the full details.

Convert ICO to HDR

Free online ICO to HDR converter. No signup required.

Drag & drop your file here

or click to browse

Max file size: 100 MB

Why Convert ICO to HDR?

Understand when and why this conversion makes sense for your workflow.

Converting ICO Image to Radiance HDR 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.

ICO Image has a known limitation: limited to relatively small image dimensions (max 256x256). In contrast, Radiance HDR Image offers a key advantage: captures a wide dynamic range of lighting from very dark to very bright. While ICO Image is commonly used for website favicons displayed in browser tabs and bookmarks, Radiance HDR Image is better suited for environment maps and image-based lighting in 3d rendering.

Our free online converter handles the ICO-to-HDR conversion in seconds, with no quality loss beyond what the target format inherently requires — no watermarks, no account needed.

ICO vs HDR: Format Comparison

Side-by-side comparison of the source and target formats.

Property	ICO (Source)	HDR (Target)
Extension	.ico	.hdr
Full Name	ICO Image	Radiance HDR Image
Compression	Varies	Varies
File Size	Large	Varies
Transparency	Yes	No
Best For	Website favicons displayed in browser tabs an…	Environment maps and image-based lighting in …
Browser Support	Varies	Varies

How to Convert ICO to HDR

Follow these simple steps to convert your file in seconds.

Upload your ICO image
Drag your .ico file onto the upload area, or click "Browse" and pick it from your device. ICO 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 HDR"
Once the upload completes, press the convert button. The image is decoded from ICO Image, color-managed where the target format requires it, and re-encoded as Radiance HDR Image. Default settings produce a sensible balance of quality and file size — no manual encoder tuning is required for typical use.
Wait for the HDR 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 .hdr file
When the conversion finishes, click the download link to save the new Radiance HDR 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 ICO to HDR

Practical advice to get the best results from this conversion.

Why this conversion is worth doing

ICO Image has a known limitation: limited to relatively small image dimensions (max 256x256). Radiance HDR Image addresses this with a key advantage: captures a wide dynamic range of lighting from very dark to very bright. Converting from ICO to HDR 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

ICO Image is most commonly used for website favicons displayed in browser tabs and bookmarks, while Radiance HDR Image is the standard for environment maps and image-based lighting in 3d rendering. If your workflow is closer to the second pattern, converting makes sense. If you are still working in a context where ICO is the norm, converting may create unnecessary compatibility friction with collaborators or tools that expect the source format.

Watch for this limitation in the HDR output

Radiance HDR Image has its own limitation worth understanding before you commit: lower precision than 32-bit EXR for demanding visual effects work. After the conversion completes, open the HDR 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

ICO and HDR 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 ICO and HDR Formats

Learn about the source and target file formats to understand what happens during conversion.

Source Format

ICO Image

image/x-icon

ICO 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

Target Format

Radiance HDR Image

image/vnd.radiance

HDR (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

Frequently Asked Questions

Common questions about converting ICO to HDR.

Related Conversions

Explore other conversions related to ICO and HDR.

Other conversions from ICO

ICO to JPG ICO to JPEG ICO to PNG ICO to GIF ICO to BMP ICO to TIFF ICO to TIF ICO to WEBP ICO to HEIC ICO to HEIF

Other conversions to HDR

JPG to HDR JPEG to HDR PNG to HDR GIF to HDR BMP to HDR TIFF to HDR TIF to HDR WEBP to HDR HEIC to HDR HEIF to HDR

Convert ICO to HDR

Why Convert ICO to HDR?

ICO vs HDR: Format Comparison

How to Convert ICO to HDR

Upload your ICO image

Click "Convert to HDR"

Wait for the HDR encode to complete

Download your .hdr file

Tips for Converting ICO to HDR

Why this conversion is worth doing

Match the format to the actual workflow

Watch for this limitation in the HDR output

Choose the right format for your content type

Understanding ICO and HDR Formats

ICO Image

Advantages

Limitations

Common Uses

Radiance HDR Image

Advantages

Limitations

Common Uses

Frequently Asked Questions

What quality should I expect from the HDR output?

What happens to transparent areas when I convert ICO to HDR?

What file size should I expect for the HDR output?

When should I convert ICO to HDR instead of staying with ICO?

What is the maximum ICO file size I can convert?

Is my ICO file safe and private when I upload it?

Related Conversions

Other conversions from ICO

Other conversions to HDR