HDR to EXR Converter
Convert HDR to EXR in your browser. HDR files usually come from HDRI environment maps, 360° panoramas and lighting simulation; EXR is the better fit for visual effects, compositing and 3D render output. You get a ZIP-compressed OpenEXR with 16-bit half-float channels, the 8-bit sRGB values converted to linear light. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
HDR expected · other image formats also work
How to use HDR to EXR
- 1
Add your HDR files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the EXR is written losslessly. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .exr files one at a time or together as a ZIP.
Why use Aback Images for hdr to exr
Where the EXR goes next
EXR opens in Nuke, Blender, Houdini, After Effects, DaVinci Resolve, Photoshop, Krita and OpenImageIO.
EXR next to HDR
Both sides are lossless, so the size depends on how well the EXR encoder handles this picture compared with the HDR's run-length encoded RGBE scanlines.
Written without a lossy pass
The EXR is written losslessly, so the pixels decoded from the HDR arrive unchanged, apart from precision beyond 8 bits per channel.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
HDR vs EXR
What changes from HDR to EXR
Encoding: the HDR uses run-length encoded RGBE scanlines; EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file, and the download is a ZIP-compressed OpenEXR with 16-bit half-float channels, the 8-bit sRGB values converted to linear light.
Bit depth: an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel in the HDR; EXR allows 16-bit half or 32-bit floating point per channel, and the EXR written here has 16-bit half float per channel. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
Colour: linear RGB (or XYZ in the XYZE variant) in the HDR; EXR supports scene-linear RGB, often ACEScg or linear Rec.709, written here as linear-light RGB.
Metadata: the HDR can carry a text header with FORMAT, EXPOSURE and optional comments; EXR can carry named header attributes such as chromaticities, timecode and camera data, but nothing is copied across.
About HDR
Radiance .hdr stores high dynamic range light values, widely used for 3D environment maps and HDRI lighting.
A Radiance file starts with '#?RADIANCE' (or '#?RGBE'), text lines such as FORMAT=32-bit_rle_rgbe and EXPOSURE, a blank line, a resolution line like '-Y 2048 +X 4096', then the scanlines.
HDR files usually come from HDRI environment maps, 360° panoramas and lighting simulation.
About EXR
OpenEXR is the high dynamic range format of film visual effects. It stores half or full floating-point channels in linear light, plus any extra render passes, and is the working format of compositing pipelines.
An EXR starts with the magic number 76 2F 31 01 and a version field, then a header of named, typed attributes (channels, compression, dataWindow, displayWindow) and a table of offsets to scanline or tile blocks.
When converting HDR to EXR makes sense
EXR is the better choice for visual effects, compositing and 3D render output, while HDR suits 3D lighting and environment maps.
EXR strengths: True high dynamic range in linear light; Any number of channels and render passes; Lossless compression options. Drawbacks to weigh: Needs tone mapping to look right on a normal screen; Very large files; No browser or phone support.
Limitations
- Light values above 1.0 are clipped rather than tone-mapped, so the sun and bright sky turn flat white.
- Environment maps are 2:1 equirectangular panoramas, so the picture looks stretched near the top and bottom, as it should.
- Files in the XYZE variant cannot be read here; RGBE files, the common kind, can.
- Compositing and 3D software read the EXR as linear light, the convention for the format, so it displays correctly there.
- The file holds colour and, when the image has transparency, an alpha channel; there are no extra render passes.
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Frequently asked questions
Does converting HDR to EXR lose quality?
EXR is written losslessly, so the pixels are stored exactly as decoded. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
Does saving as EXR add dynamic range?
No. The values come from an 8-bit image, converted to linear light so compositing software displays them correctly, but nothing brighter than the original white is invented. The file is ready to use as a plate or texture in an EXR pipeline.
Which apps open EXR files?
Nuke, Blender, Houdini, After Effects, DaVinci Resolve, Photoshop, Krita and OpenImageIO. It does not open in web browsers.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.