Open any HDRI in a real 360° sphere: drag a .hdr or .exr onto the page, ride the exposure slider, and read its resolution — all on your own machine.
Your Radiance .hdr or OpenEXR .exr is decoded to linear floating point. This HDRI viewer tone-maps that data live, so you judge the real file instead of a preview baked at one fixed exposure.
The file opens as an interactive HDRI 360 viewer: drag to look around, scroll to zoom, read the minimap to see where you are facing. A flat thumbnail hides the seam and the sky above you; an HDR image viewer built as a sphere shows both.
One slider moves the view from −6 to +6 EV. Pull it down to see whether the sun disc holds detail, push it up to read the shadow side.
Linear clips hard and tells you where the highlights truly sit. Reinhard rolls them off gently. ACES gives the filmic contrast most engines apply by default.
The info panel reports pixel dimensions, flags whether the image is exactly 2:1 equirectangular, and estimates peak luminance — the numbers that decide whether an HDRI can light a scene.
Decoding runs in a Web Worker on your own device. Nothing is uploaded, and no sign-in or credits are involved, so this HDR viewer is free to use as often as you like.
Drag a Radiance .hdr or OpenEXR .exr onto the box above, or click to pick one. Files up to 50 MB are read straight from disk — no upload, no queue.
The HDRI appears as a full 360° environment. Drag to turn, scroll to zoom, and watch the minimap to keep track of where you are facing.
Move the exposure slider and switch the tone-mapping operator until highlights and shadows both read. Both are viewfinder controls: the file on disk is never rewritten.
Confirm resolution, the 2:1 badge and peak luminance before you commit this HDRI to a render — then send it on to a cubemap, or generate a fresh one.
An HDRI is not a picture, it is a measurement: pixels run far past 1.0, and a monitor shows only a narrow window of that range at once. That is why an HDRI 360 viewer needs exposure control. The slider moves the window from −6 to +6 EV in tenth-of-a-stop steps, and the sphere re-renders from the decoded floating-point data each time, not from a cached JPEG. Drop six stops and a captured sun stays a hard bright disc; a tone-mapped fake collapses to flat grey.
The three curves answer different questions. Linear is the honest one: it multiplies and clips, so anything that blows out to white really is above the window you picked. Reinhard compresses the top end smoothly, showing whether a sky has gradient left. ACES applies the filmic S-curve Unreal, Unity and Blender use by default. All three are display maths inside this HDR viewer: they never touch the bytes on disk.
Most HDRI problems show up in three numbers, and this HDR viewer prints all three as soon as a file decodes. Resolution comes from the header, so you see it even for files a normal image viewer will not open. The aspect badge says whether the image is exactly twice as wide as tall — the only shape equirectangular projection maps cleanly onto a sphere. Peak luminance estimates how far the brightest pixel sits above diffuse white — the fastest way to tell a captured sky from an upscaled 8-bit one.
Read it as a going-in check. A 2K HDRI is fine as pure lighting and mushy as a visible backdrop; 4K earns its size only when the camera sees the sky. A peak of two or three means a low dynamic range source however the file is labelled; a peak in the hundreds means a real sun is in there.
| What the panel shows | What it means | What to check |
|---|---|---|
| Resolution | Pixel width × height from the file header | 4096 × 2048 or larger when the sky is on camera |
| 2:1 badge | Whether the image is exactly twice as wide as tall | Anything else stretches on the sphere and in your engine |
| Peak luminance | How many times brighter the hottest pixel is than diffuse white | Single digits mean soft light; hundreds mean a real sun |
Radiance .hdr and OpenEXR .exr both carry high dynamic range, but store it differently — and this page reads both. A .hdr packs three 8-bit mantissas plus a shared exponent per pixel (RGBE) — compact, and lossy at the extremes. An .exr stores real 16- or 32-bit floats per channel. As an EXR viewer, this tool widens half floats to 32-bit and expands luminance-only files to four channels, so both land in the same sphere.
The other reason people look for an EXR viewer online is the operating system. Windows has no built-in OpenEXR preview, desktop apps disagree about Radiance .hdr, and installing Blender just to glance at an environment map is a heavy answer to a small question. A browser-based HDR image viewer behaves the same on Windows, macOS, Linux and ChromeOS, because the decoder ships with the page.
An HDRI viewer is usually step one. Once the sphere looks right, the HDRI to Cubemap Converter splits the same .hdr or .exr into six floating-point cube faces for Unity, Three.js or OpenGL, keeping the range you just checked. If the file disappointed you, the AI HDRI Generator writes a fresh Radiance .hdr from a text prompt, and it lands back here for the same check.
If your image is an 8-bit JPG, PNG or WebP, this HDRI viewer turns it away on purpose — a low dynamic range panorama belongs in the 360° Panorama Viewer, built for that half of the job. When you need a game-ready sky rather than a measured one, the Skybox Generator makes a 360° environment from a prompt.
A .hdr file opens in this browser-based HDRI viewer with nothing installed: drag it onto the page and it is decoded locally into a 360° view. Photoshop or Blender are only needed to edit the file, not inspect it.
Yes — an EXR viewer online works the same on Windows, macOS, Linux and ChromeOS, because decoding happens inside the browser rather than in an OS image app. Windows has no built-in .exr preview, so a browser tab is the quickest look inside one.
Yes, this HDRI viewer is free and needs no account, no credits and no sign-in. Files are decoded on your own device, so there is no server cost to pass on and no limit beyond the 50 MB cap.
No — exposure and tone mapping are display-only controls. They change how decoded pixels are drawn to the canvas; the .hdr or .exr on your disk is never rewritten, and this page has no export.
An HDRI looks stretched when it is not exactly 2:1 equirectangular, and the info panel flags that with an amber badge. Equirectangular projection assumes twice as wide as tall, so a 16:9 or square file gets squeezed.
Peak luminance estimates how many times brighter the hottest pixel in an HDRI is than diffuse white (1.0). Single digits mean a low dynamic range source that lights softly; hundreds mean a captured sun is in the frame.
No — this HDR viewer keeps everything on your device: the file is read with the browser’s File API and decoded in a Web Worker; nothing is sent over the network.
This HDRI viewer accepts files up to 50 MB and images up to 8192 × 4096 pixels. Floating-point data unpacks large in memory, so the ceiling keeps the tab responsive.
Write a Radiance .hdr environment map from a text prompt, then open it here.
Split a .hdr or .exr into six true-HDR cube faces for Unity, Three.js or OpenGL.
The LDR half of the job: JPG, PNG and WebP panoramas, which this HDRI viewer turns away.
Generate a game-ready 360° skybox from a prompt when you have no source file.