HDR Test Online
See if this window reports high dynamic range, then use highlight and wide-gamut patterns to judge HDR tone behavior.
Live HDR readout
HDR and gamut report
This is what the browser can see: HDR capability and color gamut. It is not a nits measurement.
— Reading display…
- HDR (dynamic-range)
- —
- Video HDR
- —
- Color gamut
- —
- Color depth
- —
- Screen
- —
- Device pixels
- —
Live screen test
Start with the real patterns.
On an HDR-capable window this ramp can go brighter than SDR white. This is not a nits meter.
What it checks
Use this test when you need a clear visual answer.
HDR Test is built for quick inspection, not lab measurement. It gives you controlled browser patterns so you can decide whether the screen needs setup, retesting, or warranty attention.
Browser HDR flag
Highlight step separation
Wide color vs sRGB
If this window reports High, highlights can sit above a flat SDR white. That is a capability flag, not a nits number.
If the lightest steps merge into one white, highlight detail is gone. This is not a test video.
If the right half looks more saturated, the panel can show P3. This is not a downloadable test image.
Result guide
How to read the hdr result
Start with the hdr ramp pattern, then switch to adjacent patterns before making a decision. A real display problem usually stays in the same area when the pattern changes. A reflection, viewing angle shift, browser zoom issue, or temporary image setting often changes when you move your head, adjust brightness, or repeat the test after a restart.
Browser HDR flag
Use this page to isolate browser hdr flag under controlled screen patterns. Scan the center, edges, and corners, then confirm the same area with a second pattern before you treat it as a panel issue.
Highlight step separation
Use this page to isolate highlight step separation under controlled screen patterns. Scan the center, edges, and corners, then confirm the same area with a second pattern before you treat it as a panel issue.
Wide color vs sRGB
Use this page to isolate wide color vs srgb under controlled screen patterns. Scan the center, edges, and corners, then confirm the same area with a second pattern before you treat it as a panel issue.
Workflow
How to use the hdr test
Read the live report first. High means this display path can do HDR, not that HDR is currently on in the OS.
Open the HDR ramp fullscreen and look for extra highlight headroom beyond a flat white.
Compare P3 vs sRGB and the near-black pattern before changing TV or GPU HDR switches.
Use cases
Where this screen test is most useful
New HDR monitor
Confirm the browser can see HDR before you chase nits claims.
Laptop HDR toggle
Repeat the readout after enabling HDR in Windows or macOS.
TV browser check
Use the same page on a smart TV browser if it supports modern CSS.
Reading the result
Practical tips before you decide
Capability is not a nits number
The readout uses CSS media queries. It cannot tell you 400 nits versus 1000 nits.
OS HDR must be on
If Windows HDR or the TV HDR mode is off, the page may still report standard range.
Small highlights first
A small bright field is easier to judge than a long fullscreen peak on OLED.
Device setup
Use the same screen test across real viewing setups
The hdr test works best when the test matches the way you actually use the display. Keep the room lighting, brightness, scaling, and viewing distance close to normal, then repeat the pattern only after a setting change. This keeps the result practical instead of turning the page into a lab claim.
Desktop and laptop monitors
Use native resolution, 100 percent browser zoom, and the monitor picture mode you normally use. If you change brightness, contrast, overdrive, or color temperature, repeat the hdr pass before comparing results.
TVs, projectors, and large panels
Step back to your real viewing distance after a close inspection. Large screens can exaggerate small edge, glow, focus, or processing issues, so confirm anything suspicious with normal video, games, or desktop content.
Phones and tablets
Rotate the device if the browser supports it, clean the glass, and reduce reflections before judging the result. Some mobile browsers limit fullscreen behavior, but the same pattern sequence still helps with quick display checks.
Related tests
Continue with adjacent checks
Brightness Test
The brightness test helps you set a comfortable level while keeping near-black and near-white detail visible.
Contrast Test
Use stepped tone patterns to see whether your display keeps dark and bright details separate.
Color Accuracy Test
Compare sRGB patches, a P3 versus sRGB split, and grey fields to judge color bias and wide-gamut behavior.
OLED Screen Test
Use mid-grey, black, and checkerboard patterns to look for burn-in, retention, crushed shadows, and uneven OLED aging.
FAQ
HDR Test questions
These answers match the visible test on this page and avoid warranty or measurement claims that depend on your specific display.
How does this HDR test work?
The page reads matchMedia for dynamic-range and color-gamut, then shows highlight and P3 patterns. That tells you what this browser window can signal, not the factory peak brightness.
Why does it say standard on an HDR monitor?
HDR may be off in the OS, the window may be on an SDR screen, or the browser path is still tone-mapped. Move the window, enable HDR, and refresh.
Can a website measure DisplayHDR 400 or 1000?
No. Those ratings need a meter. Use this page to see capability and clipping, then measure if you need certified numbers.
Should I test HDR or SDR first?
Do a basic brightness and contrast pass in SDR, then turn HDR on and repeat the highlight and black checks.
Is this an HDR test video or a test image I can download?
No. This page is a live browser readout plus highlight and wide-gamut patterns. It does not play a YouTube HDR clip, and it does not download a test photo. It also cannot print nits or a DisplayHDR 400 or 1000 score.
Can I use the hdr test on more than one device?
Yes. Open the same page on each monitor, laptop, phone, tablet, TV, or projector, then compare the hdr result under similar brightness and room lighting. Device browsers can handle fullscreen differently, but the visual patterns are still useful for a practical check.
Does this online hdr test replace professional calibration?
No. This page is a browser-based visual test for finding obvious display problems and setup issues. For color-critical work, brightness targets, or measured calibration, use a hardware colorimeter or professional display workflow after the visual pass.
How to Check a Monitor for Dead Pixels
A reliable dead pixel check uses fullscreen solid colors, steady lighting, and a repeatable inspection path. The goal is to separate real panel defects from dust, reflections, scaling artifacts, and temporary cable issues.
How to Test a New Monitor
A new monitor should be tested before you mount it, remove packaging, or let the return window pass. Start with panel defects, then verify uniformity, tone, text clarity, refresh rate, and real content.
Monitor Calibration Guide
Browser tests can help you set a monitor to a sensible baseline and spot obvious problems. They do not replace a colorimeter, but they make brightness, contrast, gamma, sharpness, and banding easier to judge before hardware calibration.
Ready to inspect the full screen?
Open the fullscreen pattern and move through the test slowly.