HDR to ICO Converter
Processing entirely on your device — large files may take a moment.
Websites still expect a favicon.ico in the site root and Windows apps need ICO resources — converting from PNG takes seconds. If your files are still in HDR format, this page is the shortcut: HDR (Radiance RGBE) stores floating-point high-dynamic-range pixels — the format of lighting data and HDRI environment maps.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How HDR compares to ICO
| HDR | ICO | |
|---|---|---|
| Compression | RGBE (RLE runs) | BMP members, PNG for large sizes |
| Transparency | Not supported | Supported (1-bit or alpha) |
| Animation | Not supported | No (that is .cur/.ani) |
| Metadata | Radiance comments | None |
| Best for | Lighting data, environment maps | Favicons and Windows app icons |
How to convert HDR to ICO
- 1
Select your files
Drag & drop your HDR files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to ICO". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted ICO file individually, or grab everything at once as a ZIP archive.
About the HDR format
HDR (Radiance RGBE) is the veteran high-dynamic-range format of lighting research and 3D rendering: pixels stored as a shared 8-bit exponent plus per-channel mantissas, letting one file hold both a sun and a shadow with no clipping. HDRI environment maps for 3D scenes are almost always HDR files.
Standard image viewers show it badly or not at all, because the values can exceed what a screen can display. Converting HDR to PNG tone-maps the file into an 8-bit preview — good for quick inspection, though the floating-point original remains the render-grade master.
+ Strengths
- ✓True high-dynamic-range values
- ✓The standard of HDRI environment maps
- ✓Compact for its precision
! Limitations
- −Not display-ready — needs tone mapping
- −Viewer support is scarce
About the ICO format
ICO is the Windows icon container, and one of the oldest formats still in daily use. A single ICO file bundles several renderings of the same icon — 16×16, 32×32, 48×48 up to 256×256 — so Windows can pick the right sharpness for shortcuts, Explorer views and taskbars. Each member is stored as classic BMP data or, for large sizes, PNG compression.
On the web, favicon.ico at the site root remains the one icon request every browser makes automatically, which keeps the format alive despite cleaner alternatives like PNG and SVG icons. Keep ICOs small: every visitor downloads one.
+ Strengths
- ✓Multiple sizes bundled in one file
- ✓Every browser falls back to /favicon.ico automatically
- ✓Deep Windows integration for app icons
! Limitations
- −Practical size ceiling around 256×256
- −Windows-centric; little use outside icons
- −Quality is frozen at export time
Why convert HDR to ICO?
There is a concrete reason this conversion exists: Not display-ready — needs tone mapping ICO sidesteps that — Multiple sizes bundled in one file If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this HDR to ICO converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Will I lose quality converting HDR to ICO?
No — ICO is a lossless format, so every pixel of the converted image matches your original HDR file. You can also adjust the quality/size balance before converting when the target format supports compression.
What happens to EXIF data and other metadata?
Conversions here re-encode the image, and re-encoding generally does not carry the original metadata over. If the EXIF data of your HDR files matters (camera model, GPS, timestamps), keep the original file as the master and treat the converted copy as the shareable version.
Can I convert several HDR files at once?
Yes — drop as many files as you like into the tool and they are converted in one batch. When more than one file comes out, everything is bundled into a ZIP for a single download.