Monitor HDR Tiers Explained: HDR400, HDR600, and HDR1000 and What Actually Changes

A monitor box printed with "HDR400" and one printed with "HDR1000" both technically support HDR, but the gap between what they actually show on screen is closer to the gap between SDR and HDR than the numbers suggest.

VESA's DisplayHDR certification program was built to give buyers a reference point beyond a vague "HDR ready" sticker, and the number in each tier's name refers to minimum peak brightness in nits the panel must sustain during a 10% window test. That part is straightforward. What gets lost is that each tier also carries separate requirements for black level, contrast ratio, color bit depth, and color gamut coverage, and the lower tiers were designed to let panels that don't have the hardware for real HDR still qualify for a badge.

HDR400: the certification that doesn't require local dimming

DisplayHDR 400 requires 400 nits peak brightness, 8-bit color (sometimes via dithering from a native 6-bit panel), and Rec. 709 color coverage. Critically, it does not require any local dimming zones and does not require a meaningfully lower black level than a standard SDR panel. Without local dimming, a monitor can't selectively darken parts of the screen while keeping other parts bright, which is the mechanism that produces HDR's signature look: a bright highlight next to deep black in the same frame. An HDR400 panel raises overall brightness on HDR content but can't produce that simultaneous contrast, so bright scenes often look washed out rather than punchy, and dark scenes show elevated black levels compared to what the same panel does in SDR mode with local contrast enhancement disabled.

This is why HDR400 has a reputation among enthusiasts as "HDR in name only" — it satisfies the technical letter of the certification without delivering the visual effect most people associate with the term. Buyers who compare an HDR400 monitor's marketing photos to what they see in person are often disappointed for exactly this reason, and it isn't a defective unit; it's the tier doing what it was specified to do.

HDR600: the first tier with meaningful requirements

DisplayHDR 600 raises peak brightness to 600 nits and adds a genuine black level requirement along with local dimming in most implementations (edge-lit or basic full-array backlighting with a modest zone count). Color requirements step up to wider gamut coverage as well. This is the first tier where a panel typically has enough hardware behind it — brightness headroom plus some ability to dim dark regions independently — to show a visible difference between SDR and HDR content side by side. The difference is still limited by zone count; a backlight with a few dozen zones across a 27-inch panel still produces blooming (a visible halo) around bright objects against dark backgrounds, because each zone covers a fairly large area and can't isolate a small bright point precisely.

HDR1000 and true full-array local dimming

DisplayHDR 1000 requires 1000 nits peak brightness alongside strict black-level and contrast requirements that in practice demand a full-array local dimming backlight with a meaningfully higher zone count, or a self-emissive panel technology like OLED or Mini-LED where dimming granularity is far finer. At this tier, bright highlights and deep blacks can coexist in the same frame with much less blooming, and the brightness headroom is enough to make specular highlights (glints of light off metal or water, for instance) genuinely stand out rather than just look "brighter than everything else." This is the tier where HDR starts to look like the marketing demos rather than a slightly brighter SDR image.

OLED and true Mini-LED panels frequently exceed even the 1000-nit tier's minimums in per-pixel or fine-zone contrast even when their sustained full-screen brightness is lower, because their advantage is control precision rather than raw peak output. A gaming monitor with excellent OLED contrast but a peak brightness under 1000 nits in a small highlight window can still look more convincingly HDR than an edge-lit LCD hitting the 1000-nit number across a larger area, which is a case where the spec sheet number and the perceived result diverge.

What this means when comparing monitors on a spec sheet

The DisplayHDR tier tells you the brightness floor and the general hardware class, but it doesn't tell you zone count, backlight layout, or how good the dimming algorithm is at avoiding blooming and haloing artifacts — those details usually only show up in independent reviews with actual local dimming zone maps and blooming photography. Treating HDR400 as "has HDR" and HDR600/HDR1000 as "actually does something with it" is a reasonable rule of thumb, and checking a specific model's zone count before buying for HDR content is worth the extra five minutes for anyone buying primarily for movies or HDR-graded games rather than competitive shooters where color accuracy in bright HDR scenes matters less than raw refresh rate.