Why does this checker say No when I know my monitor supports HDR?

This tool reports the live HDR state of your current browser session, not your monitor's hardware capability. A capable display shows No whenever HDR is switched off at the OS level, when your cable or port doesn't have enough bandwidth at your current resolution and refresh rate, or when the browser itself isn't compositing in HDR even though the OS is.

What's the difference between the HDR Active and Video HDR Active results?

HDR Active reflects the dynamic-range media query — the general display compositing state. Video HDR Active reflects the video-dynamic-range media query specifically for video playback. They can disagree: a system can report HDR active in general while video playback still falls back to standard dynamic range, usually because of the codec or playback path in use.

What is HDR and why does it matter for displays?

HDR (High Dynamic Range) allows displays to show a much wider range of brightness and color compared to standard SDR screens. HDR content features deeper blacks, brighter highlights, and more vivid colors, resulting in a more lifelike and immersive viewing experience for movies, games, and photos.

What is DisplayHDR certification and how are the tiers defined?

DisplayHDR is an open standard from VESA that certifies monitors at specific performance tiers: HDR400, HDR600, HDR1000, and HDR1400 (plus True Black variants for OLED). Each tier sets minimum requirements for peak luminance, color gamut, bit depth, and black level. Only displays meeting all spec requirements may carry the official DisplayHDR logo.

What peak brightness (nits) do I need for HDR?

The minimum for entry-level HDR is 400 nits (DisplayHDR 400), but a noticeable HDR experience typically starts at 600 nits or higher. For premium HDR with specular highlights that truly pop, 1000 nits or more is recommended. OLED displays can qualify with lower brightness due to their perfect black levels.

What is the difference between HDR10, HDR10+, and Dolby Vision?

HDR10 is the baseline open standard supported by most HDR content and displays. HDR10+ adds dynamic metadata that adjusts tone mapping scene-by-scene, developed by Samsung and Amazon. Dolby Vision is a proprietary format from Dolby that also uses dynamic metadata and generally delivers the highest quality, but requires a license fee from manufacturers.

Does bit depth affect HDR quality?

Yes, significantly. HDR content is mastered at 10-bit color depth, which provides over a billion colors compared to 8-bit's 16.7 million. A true 10-bit or 12-bit panel avoids color banding and reproduces subtle gradients accurately. Many budget displays use 8-bit+FRC dithering, which approximates 10-bit but with compromises.

Can my OLED display qualify for HDR even with lower peak brightness?

Yes. OLED panels achieve near-perfect black levels (0.0001 nits or lower), which produces an extremely high contrast ratio. VESA's DisplayHDR True Black certification is specifically designed for OLED and similar self-emissive technologies, recognizing that ultra-low black levels can deliver excellent HDR quality even at lower peak brightness than LCD panels.

HDR Support Checker

The HDR Support Checker queries your browser's live dynamic range state and reports whether your session is currently rendering in high dynamic range — not whether your monitor is HDR-capable, but whether HDR is actually switched on right now. A capable display with HDR toggled off in your OS settings will honestly report No here, and the diagnostic list below explains exactly why that happens. Use the free scrollbar width checker to confirm everything looks correct before you rely on it elsewhere.

HDR Status Right Now

--HDR Active

--Video HDR Active

This checker reads one specific, live signal from your browser: whether the page is currently being composited in high dynamic range. It does this through two CSS media queries — dynamic-range for the display in general and video-dynamic-range for video playback specifically — both exposed directly by the browser, with no plugin or download involved.

Live Status, Not a Capability Test

A "No" result here does not mean your monitor can't do HDR. It means HDR isn't switched on for this browsing session right now. Those are different questions, and the gap between them is where most confusion comes from: a genuinely HDR-capable panel with HDR toggled off in your operating system will honestly report No, because as far as the browser's compositor is concerned, nothing HDR is happening at this moment. A quick pass through the color gamut checker online catches issues before they become real problems.

The two results can also disagree with each other. dynamic-range: high reflects the general display pipeline state, while video-dynamic-range: high reflects specifically whether video content can be rendered in HDR — a system can pass one and not the other, for example when the OS-level HDR toggle is on but the browser itself isn't compositing video through an HDR-capable path.

Why a Capable Display Can Still Report No

If you know your monitor supports HDR but this page reports No, work through these in order — they cover the overwhelming majority of cases: A quick pass through the viewport size checker online catches issues before they become real problems.

HDR is off at the OS level. Windows requires HDR to be explicitly enabled per-display in Settings → Display; macOS requires it enabled in System Settings → Displays. The browser inherits whatever the OS reports, so this is the first thing to check.
Cable or port bandwidth is short. HDR adds bit depth on top of your existing resolution and refresh rate, and older HDMI/DisplayPort cables or ports can run out of bandwidth at high resolution-plus-refresh-rate combinations, silently falling back to SDR rather than failing outright.
The browser itself isn't compositing in HDR even though the OS reports HDR support. This varies by browser and by GPU driver version — an outdated browser build is a common cause.
The display is in a mode that doesn't request HDR. Some monitors need HDR enabled in their own on-screen-display menu in addition to the OS setting, particularly on older or budget panels with a separate HDR toggle.

HDR10, HDR10+, and Dolby Vision — Why the Format Matters

Even once HDR is active, not all HDR content is encoded the same way. HDR10 is the open baseline format that essentially every HDR display and most HDR content supports — it uses static metadata, meaning the same brightness and color mapping applies across an entire piece of content. HDR10+, developed by Samsung and Amazon, and Dolby Vision, Dolby's proprietary format, both add dynamic metadata that adjusts tone mapping scene-by-scene instead of once for the whole title — in practice this means better-preserved highlight and shadow detail in scenes with big brightness swings. Dolby Vision requires a licensing fee from device manufacturers, which is why it's less universally supported than HDR10. The display specs report runs entirely in your browser — nothing you enter is ever sent to a server.

DisplayHDR Certification Tiers

Because "HDR support" on a spec sheet can mean almost anything, VESA's DisplayHDR is an open, publicly documented certification that sets minimum requirements a panel must actually measure up to before it can carry the badge — peak brightness, black level, color gamut coverage, bit depth, and backlight dimming behavior are all specified per tier.

DisplayHDR Tier	Peak Luminance	Color Gamut (DCI-P3)	Bit Depth	Backlight Dimming
DisplayHDR 400	400 cd/m²	≥90% (optional)	8-bit	Not required
DisplayHDR 600	600 cd/m²	≥90%	8-bit	Required
DisplayHDR 1000	1000 cd/m²	≥90%	10-bit	Required, full-array local dimming
DisplayHDR True Black 400	400 cd/m²	≥90%	10-bit	Per-pixel (OLED/MicroLED)

The "True Black" tiers exist because OLED and MicroLED panels achieve deep black levels a different way than LCD does — per-pixel emission instead of a backlight dimmed in zones — so VESA scores them against a separate bar that credits that near-zero black level rather than requiring the same peak brightness an LCD needs to look equally impressive.

None of this changes what this page reports, though: DisplayHDR describes what a panel is capable of, while the status above describes what your browser is doing right now. A DisplayHDR 1000-certified monitor with HDR switched off in Windows will still show No here, correctly.

Frequently Asked Questions

Why does this checker say No when I know my monitor supports HDR?: This tool reports the live HDR state of your current browser session, not your monitor's hardware capability. A capable display shows No whenever HDR is switched off at the OS level, when your cable or port doesn't have enough bandwidth at your current resolution and refresh rate, or when the browser itself isn't compositing in HDR even though the OS is.
What's the difference between the HDR Active and Video HDR Active results?: HDR Active reflects the dynamic-range media query — the general display compositing state. Video HDR Active reflects the video-dynamic-range media query specifically for video playback. They can disagree: a system can report HDR active in general while video playback still falls back to standard dynamic range, usually because of the codec or playback path in use.
What is HDR and why does it matter for displays?: HDR (High Dynamic Range) allows displays to show a much wider range of brightness and color compared to standard SDR screens. HDR content features deeper blacks, brighter highlights, and more vivid colors, resulting in a more lifelike and immersive viewing experience for movies, games, and photos.
What is DisplayHDR certification and how are the tiers defined?: DisplayHDR is an open standard from VESA that certifies monitors at specific performance tiers: HDR400, HDR600, HDR1000, and HDR1400 (plus True Black variants for OLED). Each tier sets minimum requirements for peak luminance, color gamut, bit depth, and black level. Only displays meeting all spec requirements may carry the official DisplayHDR logo.
What peak brightness (nits) do I need for HDR?: The minimum for entry-level HDR is 400 nits (DisplayHDR 400), but a noticeable HDR experience typically starts at 600 nits or higher. For premium HDR with specular highlights that truly pop, 1000 nits or more is recommended. OLED displays can qualify with lower brightness due to their perfect black levels.
What is the difference between HDR10, HDR10+, and Dolby Vision?: HDR10 is the baseline open standard supported by most HDR content and displays. HDR10+ adds dynamic metadata that adjusts tone mapping scene-by-scene, developed by Samsung and Amazon. Dolby Vision is a proprietary format from Dolby that also uses dynamic metadata and generally delivers the highest quality, but requires a license fee from manufacturers.
Does bit depth affect HDR quality?: Yes, significantly. HDR content is mastered at 10-bit color depth, which provides over a billion colors compared to 8-bit's 16.7 million. A true 10-bit or 12-bit panel avoids color banding and reproduces subtle gradients accurately. Many budget displays use 8-bit+FRC dithering, which approximates 10-bit but with compromises.
Can my OLED display qualify for HDR even with lower peak brightness?: Yes. OLED panels achieve near-perfect black levels (0.0001 nits or lower), which produces an extremely high contrast ratio. VESA's DisplayHDR True Black certification is specifically designed for OLED and similar self-emissive technologies, recognizing that ultra-low black levels can deliver excellent HDR quality even at lower peak brightness than LCD panels.