HDR to GZ Converter
Processing entirely on your device — large files may take a moment.
Radiance HDR Image and Gzip Compressed File exist for different jobs: HDR (Radiance RGBE) stores floating-point high-dynamic-range pixels — the format of lighting data and HDRI environment maps. Unpack a .gz into a normal file or repack it as ZIP/TAR when the receiving tool does not understand gzip.
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 GZ
| HDR | GZ | |
|---|---|---|
| Compression | RGBE (RLE runs) | DEFLATE |
| Best for | Lighting data, environment maps | Logs, dumps, datasets |
How to convert HDR to GZ
- 1
Select your files
Select your HDR file.
- 2
Convert instantly
The file bytes are gzip-compressed in place — the same archive your server or build tool produces, made locally.
- 3
Download results
Download the .gz file — ready to upload, serve or attach.
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 GZ format
A .gz file is one file squeezed by gzip — not an archive. kernel.org tarballs are “tar inside gz”, but plenty of logs, JSON dumps and CSV exports travel as plain .gz. Opening one means decompressing it back to the original bytes.
Repacking into ZIP or TAR gives the decompressed file a container that every GUI tool opens without a second thought.
+Strengths
- ✓Everywhere on Linux and macOS
- ✓Fast, well-understood compression
- ✓Streams natively from any tool
!Limitations
- −Single file only — no directory tree
- −No encryption or integrity metadata
Why convert HDR to GZ?
Think of it as moving your file to the container that fits the job. Not display-ready — needs tone mapping GZ works differently: Everywhere on Linux and macOS 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 GZ 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 GZ?
No — GZ 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.
Is there a size limit for archive conversion?
There is no upload cap because nothing is uploaded — the practical limit is your device memory. A few hundred megabytes of unpacked content works comfortably on a modern computer.
Are the files inside my HDR archive modified?
No. Contents are unpacked in memory and repacked into GZ byte-for-byte — the conversion changes the container, never the files inside it.