What specs actually matter in a 4K TV

Almost every mid-size and large TV sold today is "4K", so resolution alone no longer separates a good TV from a disappointing one. What matters is how the TV handles contrast, brightness, colour and motion — and whether it has the connections your devices need. Here is what to look at, roughly in order of importance for most people.

4K resolution: the baseline

Consumer 4K TVs, also sold as Ultra HD or UHD, have a resolution of 3840 × 2160 pixels. That is twice the width and twice the height of 1080p Full HD, so four times as many pixels. Cinema 4K is slightly wider, at 4096 × 2160, but that format is not used by TVs. The extra detail is easiest to see on larger screens and when you sit relatively close.

Contrast and panel type

Contrast — the difference between the darkest and brightest parts of the picture — shapes picture quality more than any other single factor.

• OLED panels light each pixel individually, so black areas can be completely dark. They offer excellent contrast and wide viewing angles; very bright rooms and long periods of static images are the points to consider.
• LED/LCD TVs use a backlight behind the panel. Models with local dimming, including Mini-LED designs, can dim parts of the backlight to improve contrast; the number of dimming zones and how well they are controlled make a big difference.
• VA or IPS LCD panels: VA panels usually have better contrast, while IPS panels usually keep colours more consistent when viewed from the side.

HDR: formats and real brightness

High dynamic range (HDR) lets a TV show brighter highlights and more detail in dark and bright areas than standard dynamic range. Standard content is limited to roughly 100 nits, while HDR content is often mastered at 1,000 nits or more. How impressive HDR looks therefore depends heavily on how bright the TV can actually get: a TV that accepts an HDR signal but cannot get much brighter than an ordinary set will show little benefit.

The main HDR formats are:

• HDR10 — the open and most widespread format. It uses static metadata, one set of instructions for the whole film.
• HDR10+ and Dolby Vision — both use dynamic metadata, which can adjust scene by scene. Dolby Vision is proprietary and licensed; HDR10+ is free for content creators.
• HLG — developed by the BBC and NHK for broadcast TV; it is royalty-free and works on standard-range UHD displays too.

Practically every HDR TV supports HDR10. Check which other formats your streaming services, discs or consoles use before paying extra for one of them. HDR content uses 10-bit (or 12-bit) colour to avoid visible banding, and HDR is often paired with a wide colour gamut.

Refresh rate and motion

Most TVs have a native refresh rate of either 60 Hz or 120 Hz. A true 120 Hz panel gives smoother motion in sports and makes 4K at 120 frames per second possible for consoles and PCs. Be careful with labels such as "motion rate 240": they usually describe image processing, not the panel's native refresh rate.

HDMI 2.1 features for gaming

If you play on a recent console or PC, look for HDMI ports that support HDMI 2.1 features:

• 4K at 120 Hz for smoother gameplay;
• VRR (Variable Refresh Rate), which reduces stutter and tearing;
• ALLM (Auto Low Latency Mode), which switches the TV to its low-latency mode automatically;
• eARC, for sending high-quality audio to a soundbar or receiver.

Not every HDMI port on a TV supports every feature, so check which ones do. The highest-bandwidth connections need an Ultra High Speed HDMI Cable, which HDMI Licensing Administrator specifies for systems of up to 48 Gbps.

Sound

Thin TVs have little room for speakers. If clear dialogue matters to you, budget for a soundbar — an eARC port makes connecting one simpler.

Smart features and updates

The built-in platform decides which streaming apps you get and for how long they are updated. If you already use a streaming stick or box, the TV's own platform matters less.

Size and viewing distance

Measure the space and the distance to your seat before choosing a size. As a rough rule, larger screens benefit more from 4K detail, but a TV that dominates a small room can be tiring to watch.

Labels to treat with caution

• Contrast ratios such as "dynamic contrast 1,000,000:1" without a stated measurement method.
• "HDR" on its own, without information about brightness or local dimming.
• Upscaling claims: every 4K TV upscales lower-resolution content, but the quality varies.

Quick checklist

1. Choose the panel for your room: OLED for contrast in darker rooms, a bright LCD with good local dimming for bright rooms.
2. Look for real HDR brightness, not just an HDR logo.
3. Check which HDR formats your content uses.
4. Gamers: native 120 Hz, VRR, ALLM and at least one HDMI 2.1 port.
5. Plan for a soundbar if dialogue clarity matters.
6. Measure your space before you pick a size.

Two TVs that match this checklist

The TCL T7 Series brings a native 120 Hz panel, VRR and every major HDR format at a value price — a strong fit for the checklist above, especially in brighter rooms. The LG C5 is the upgrade for darker rooms and gaming: self-lit OLED pixels give true blacks, and it supports up to 144 Hz.

As our catalog grows, RightDeals will compare TV offers from several stores side by side and show when each price was last checked. Until then, the links above take you to Amazon, where you can check the current price.