EXR to HDR Converter
Convert EXR to HDR in your browser. EXR files usually come from 3D renderers and compositing in Nuke, Blender, Houdini, After Effects and DaVinci Resolve; HDR is the better fit for 3D lighting and environment maps. You get a Radiance RGBE (.hdr) file, with 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
EXR expected · other image formats also work
How to use EXR to HDR
- 1
Add your EXR files: drop them here, choose them, or paste from the clipboard.
- 2
Pick the colour that replaces transparent areas, since HDR has none.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .hdr files one at a time or together as a ZIP.
Why use Aback Images for exr to hdr
Where the HDR goes next
HDR opens in Blender, Photoshop, Houdini, Unreal Engine, Unity and Affinity Photo.
HDR next to EXR
Both sides are lossless, so the size depends on how well the HDR encoder handles this picture compared with the EXR's none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file.
Written without a lossy pass
The HDR is written losslessly, so the pixels decoded from the EXR 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.
EXR vs HDR
What changes from EXR to HDR
Encoding: the EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file; HDR uses run-length encoded RGBE scanlines, and the download is a Radiance RGBE (.hdr) file, with the 8-bit sRGB values converted to linear light.
Bit depth: 16-bit half or 32-bit floating point per channel in the EXR; HDR allows an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel, and the HDR written here has RGBE, 32 bits per pixel. Floating-point values are mapped to 8 bits per channel, and anything brighter than white clips.
Colour: scene-linear RGB, often ACEScg or linear Rec.709 in the EXR; HDR supports linear RGB (or XYZ in the XYZE variant), written here as linear-light RGB.
Transparency: the EXR stores it as an A channel stored like any other channel; the HDR has none, so transparent areas are filled with the colour you choose.
Other images: the EXR can hold extra channels (depth, normals, render passes) and multiple parts; only the main image is converted.
Metadata: the EXR can carry named header attributes such as chromaticities, timecode and camera data; HDR can carry a text header with FORMAT, EXPOSURE and optional comments, but nothing is copied across.
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.
EXR files usually come from 3D renderers and compositing in Nuke, Blender, Houdini, After Effects and DaVinci Resolve.
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.
When converting EXR to HDR makes sense
HDR is the better choice for 3D lighting and environment maps, while EXR suits visual effects, compositing and 3D render output.
HDR strengths: True high dynamic range; Standard for HDRI environment maps. Drawbacks to weigh: Needs tone mapping to view on normal screens.
Limitations
- EXR values are scene-linear and can exceed 1.0; they are mapped to display values without tone mapping, so highlights clip to white.
- Only the colour channels are converted; depth, normals and other render passes are dropped.
- Single-part scanline files are supported; tiled, deep and multi-part EXRs, and those compressed with B44 or DWA, cannot be read here.
- 3D software treats the file as linear light, so an ordinary photo used as an environment map may need its exposure raised to light a scene well.
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Frequently asked questions
Does converting EXR to HDR lose quality?
HDR is written losslessly, so the pixels are stored exactly as decoded. Floating-point values are mapped to 8 bits per channel, and anything brighter than white clips. Not carried over: any extra channels.
What happens to transparency when converting EXR to HDR?
EXR stores transparency as an A channel stored like any other channel. HDR has no alpha channel, so transparent pixels are composited onto a solid colour, white unless you pick another. To keep transparency, convert to PNG, WebP or AVIF instead.
Does saving as HDR make a real HDRI?
No. A real HDRI is merged from several exposures. This file holds an 8-bit image in linear light, so 3D software reads it correctly, but it has no more range than the source.
Which apps open HDR files?
Blender, Photoshop, Houdini, Unreal Engine, Unity and Affinity Photo. 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.