HDR to QOI Converter
Processing entirely on your device — large files may take a moment.
Radiance HDR Image and Quite OK Image exist for different jobs: HDR (Radiance RGBE) stores floating-point high-dynamic-range pixels — the format of lighting data and HDRI environment maps. QOI is popular with hobbyist engines and emulators; convert to PNG to view it anywhere.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How HDR compares to QOI
| HDR | QOI | |
|---|---|---|
| Compression | RGBE (RLE runs) | Lossless (RLE/delta) |
| Transparency | Not supported | Supported |
| Animation | Not supported | Not supported |
| Metadata | Radiance comments | None |
| Best for | Lighting data, environment maps | Hobby engines, lossless simplicity |
How to convert HDR to QOI
- 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 QOI". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted QOI 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 QOI format
QOI (Quite OK Image, 2021) is a lossless format defined in one short specification document: a stream of simple run-length and delta ops over linear pixels. An encoder fits in 300 lines, decodes faster than PNG, and compresses comparably for photographic content.
It has found a home in emulators, demoscene projects and hobby engines — anywhere people want images without a codec dependency. Viewers rarely support it, so converting QOI to PNG is the way to bring these files into normal tools.
+ Strengths
- ✓Radically simple spec (~200 lines)
- ✓Lossless with fast decode
- ✓No patent or licensing questions
! Limitations
- −Almost no viewer support
- −Larger than modern codecs for many images
Why convert HDR to QOI?
Think of it as moving your file to the container that fits the job. Not display-ready — needs tone mapping QOI works differently: Radically simple spec (~200 lines) If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this HDR to QOI 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 QOI?
No — QOI 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.
Will transparent areas survive the conversion to QOI?
Transparency is kept whenever QOI actually supports an alpha channel. If the target format has none (like JPG), transparent areas are flattened onto a white background — that is a property of the format, not of this tool.
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.