J2K to HDR Converter
Processing entirely on your device — large files may take a moment.
JPEG 2000 Codestream and Radiance HDR Image exist for different jobs: J2K is the raw codestream spelling of JPEG 2000 — the same wavelet image without the JP2 container wrapper. Converting HDR to PNG produces a tone-mapped preview usable in any image viewer.
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 J2K compares to HDR
| J2K | HDR | |
|---|---|---|
| Compression | Wavelet (lossy + lossless) | RGBE (RLE runs) |
| Transparency | Supported | Not supported |
| Animation | Not supported (MJ2 is separate) | Not supported |
| Metadata | XML boxes (EXIF/GPS) | Radiance comments |
| Best for | Archives, medical, cinema | Lighting data, environment maps |
How to convert J2K to HDR
- 1
Select your files
Drag & drop your J2K 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 HDR". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted HDR file individually, or grab everything at once as a ZIP archive.
About the J2K format
JPEG 2000 (JP2) replaced JPG's DCT blocks with wavelet transforms: at the same bitrate it shows fewer blocky artifacts, and its lossless mode compresses better than JPG ever could. It was the format of early digital cinema and remains common in archives, medical systems and geospatial pipelines.
Browser support never arrived — Chrome, Firefox and Safari all skip it — so a JP2 file is often invisible on the web. Converting JP2 to JPG or PNG makes archival material viewable anywhere; converting the other way gives long-term storage better compression.
+Strengths
- ✓True lossless mode
- ✓Better quality per byte than JPG
- ✓ROI / progressive decoding built in
!Limitations
- −No browser support
- −Slow to encode compared to JPG
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
Why convert J2K to HDR?
There is a concrete reason this conversion exists: No browser support HDR sidesteps that — True high-dynamic-range values If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this J2K to HDR 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 J2K to HDR?
No — HDR is a lossless format, so every pixel of the converted image matches your original J2K file. You can also adjust the quality/size balance before converting when the target format supports compression.
Can I convert several J2K 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.
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 J2K files matters (camera model, GPS, timestamps), keep the original file as the master and treat the converted copy as the shareable version.