Live capability detection, wide-gamut color swatches, and shadow/highlight patterns — a genuine look at whether your display, OS, and browser are actually aligned for HDR right now.
RUNS ENTIRELY IN YOUR BROWSER · NOTHING IS RECORDED OR UPLOADED
Last updated: · Reviewed for accuracy against current browser APIs
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Checking what your browser and operating system currently report…
Live capability detection
Wide-gamut color comparison
Left is standard sRGB. Right is the same hue pushed into Display P3 / Rec.2020 — on a true wide-gamut screen with an active wide-gamut pipeline, the right side should look distinctly more saturated.
sRGB red
Display P3 red
sRGB green
Display P3 green
sRGB blue
Display P3 blue
Shadow & highlight detail
A display handling dynamic range well should let you distinguish every step on both ends, not just one.
It reads what your browser and OS currently report — but only if HDR is actually turned on in your system settings.
Turn on HDR in your OS if it shows as off.
Windows: Settings → System → Display → HDR. macOS: System Settings → Displays, enable High Dynamic Range on a supported external display.
Recheck the detection panel.
It should update once HDR is genuinely active at the OS level.
Compare the wide-gamut swatches.
On a true P3 or Rec.2020 display with the right pipeline active, the right-hand swatches should look distinctly more saturated.
Check the shadow and highlight patterns.
A genuine HDR-capable panel should hold detail at both ends at once, not just one.
Why HDR is a mode, not a property
It's tempting to think of HDR as something a monitor simply "has," the way it has a resolution or a size. In practice it's closer to a mode that three separate layers all have to agree to use at the same time: the physical display has to be capable of it, your operating system has to have HDR switched on for that specific screen, and whatever you're watching — a browser, a game, a video app — has to actually be sending HDR content rather than ordinary SDR.
Break any one link in that chain and the result looks flat and washed out rather than obviously broken, which is exactly why detection is worth checking directly instead of assuming. The detection panel above reads standard browser media features — dynamic-range, color-gamut, and screen.colorDepth — that reflect what your OS is currently exposing to the browser. If HDR is switched off in your system settings, this will correctly report it as unavailable even on a monitor that's fully capable of it once you turn it on. If you want to check color banding specifically, independent of HDR mode, our Gradient Test isolates that with a cleanly generated gradient.
Turning on HDR, by operating system
Windows 10 & 11
Open Settings → System → Display and turn on the "HDR" toggle for the display you're using. Windows also ships an HDR Calibration app worth running afterward, since default HDR brightness and color settings are rarely well-tuned out of the box. If the toggle is missing or greyed out entirely, an outdated graphics driver is a common cause — check NVIDIA, AMD, or Intel for the latest version before assuming the monitor itself doesn't support it.
macOS
On a MacBook with a built-in HDR-capable display, macOS enables HDR automatically for supported content. For an external monitor, connect it over a video output that supports HDR (USB-C, DisplayPort, or HDMI 2.0+) and check System Settings → Displays for a High Dynamic Range option on that specific display.
A note on browsers
Support for detecting and rendering HDR varies by browser even with the OS configured correctly — on macOS specifically, Safari has historically had more consistent HDR handling than Chrome or Firefox for some content types. If detection looks wrong in one browser, it's worth trying a second before concluding the display itself is at fault.
Understanding DisplayHDR tiers
VESA's DisplayHDR certification exists specifically to cut through marketing language, since "HDR" alone on a spec sheet says almost nothing about real performance.
Tier
What it generally indicates
DisplayHDR 400
Minimum peak brightness requirement, often without local dimming — frequently criticized as barely-HDR
DisplayHDR 600 / 1000 / 1400
Progressively higher peak brightness, generally paired with better dimming control at higher tiers
DisplayHDR True Black
Reserved for OLED and similar self-emissive panels — near-zero black levels alongside high brightness
A monitor with no local dimming zones at all — a plain edge-lit LCD carrying only a base HDR400 badge — often can't show deep blacks and bright highlights in the same frame, which is the entire point of HDR. It's genuinely possible for content to look worse in HDR mode on hardware like this than the same content in ordinary SDR.
HDR vs. wide color gamut
These two get bundled together constantly because most HDR content also uses a wide color gamut, but they're answering different questions. HDR is about the range between the darkest and brightest values a display can show in the same image. Wide color gamut — Display P3 or Rec.2020, tested by the swatches above — is about how many distinct, especially how saturated, colors a display can reproduce at all. A display can technically support one without the other, though in current hardware they usually arrive together.
The honest limits of this test
This tool can tell you what your browser and OS currently report, and give you visual patterns to judge by eye — it cannot measure your display's actual peak brightness in nits, verify a specific DisplayHDR certification, or confirm true 10-bit panel hardware. Those all need a physical light meter or colorimeter, the kind of equipment dedicated review sites use, not anything a browser tab can access. Treat the detection panel as a genuinely useful first check on whether your setup is even configured correctly, not a substitute for your monitor's actual certified specifications.
Frequently asked questions
Why does this say HDR isn't supported when my monitor is HDR-certified?
HDR requires three things working together: an HDR-capable display, HDR turned on in your operating system for that specific output, and a browser or app actually sending HDR content. If HDR is off in Windows or macOS settings, the browser will correctly report it as unavailable even on a fully HDR-capable monitor.
What's the difference between HDR and wide color gamut?
HDR is about the range between the darkest and brightest parts of an image showing up together. Wide color gamut (like Display P3 or Rec.2020) is about how many distinct colors a display can show. Most HDR content uses a wide gamut, but a display can support one without the other.
Is "HDR400" real HDR?
Technically it carries a VESA badge, but many HDR400 monitors are ordinary edge-lit LCDs with no local dimming, peaking at only 400 nits. Without zoned dimming, they often can't show deep blacks and bright highlights at once — HDR's actual point.
Can this test measure my display's actual peak brightness?
No. Peak brightness in nits needs a physical light meter or colorimeter. This test can only report what your system says about HDR and gamut support, and show visual patterns to judge by eye.
Why do the wide-gamut swatches look identical on my screen?
Either your display doesn't cover the P3 or Rec.2020 gamut, your OS or browser isn't currently using a wide-gamut pipeline, or both. Any weak link in that chain makes the enhanced swatch fall back to looking the same as the standard one.
Does this tool record or upload anything?
No. Detection reads standard browser capability APIs locally, and every pattern is drawn in your browser — nothing is captured, recorded, or sent anywhere.
More tools on ProDeviceTest
HDR is one piece of overall display quality. These cover the rest.
Gradient Test — check color banding and bit-depth issues
ProDeviceTest