What Are Nits? Display Brightness Explained

A nit is a measure of luminance: how much light a surface sends towards the viewer from each square meter of its area. One nit equals one candela per square meter (cd/m²), and the two are used interchangeably on datasheets. The name comes from the Latin nitere, to shine. The SI writes it as cd/m², while the display industry mostly says nits.

Because it is measured per square meter, the nit figure does not depend on screen size. A 7 inch display and a 32 inch display both rated at 1,000 nits look equally bright to the eye, even though the larger screen puts out far more light in total. That makes nits the right figure for comparing screens, and it is the figure datasheets quote as brightness.

Three light measures turn up when people compare screens, projectors and lighting, and they answer different questions.

The right brightness depends on the light around the screen. Too dim and the image washes out, too bright and the screen wastes power, runs hot and tires the eyes in a dark room.

The figures assume a screen with low reflection. Optical bonding and anti-reflective glass can matter as much as the backlight, because reflected glare adds to every pixel and washes out contrast. Our industrial monitors cover the indoor range, while our sunlight readable monitors list the brightness of every model for outdoor sites.

A single nit figure can hide a lot. Consumer TVs and phones often quote peak brightness, measured on a small bright patch for a few seconds. Full-screen brightness held for minutes is usually much lower, because the panel limits power and heat. HDR certifications such as VESA DisplayHDR test both peak and sustained levels, and our explainer on HDR monitors covers the tiers.

Industrial monitor datasheets normally quote typical full-white brightness at the centre of the screen, measured with a photometer. That is the more useful number for an HMI or outdoor display that shows bright backgrounds all day. When you compare models, check that both figures were measured the same way.

Brightness is only half of what makes a screen readable. Contrast compares the brightest white with the darkest black, and in bright rooms the light reflected off the screen raises the black level, so a brighter backlight is often used to win back contrast that glare has taken away. Our guide to monitor contrast ratio explains how the two interact.

Uniformity is the third figure worth checking. Datasheets usually quote brightness at the centre of the screen, and the corners of an edge-lit panel can be noticeably dimmer. Better panels quote uniformity as a percentage, measured at several points across the screen, which matters on large monitors and on video walls where screens sit side by side.

On an industrial screen, brightness is a design decision with knock-on effects. A higher-brightness LED backlight draws more power and produces more heat, which a sealed or fanless enclosure has to shed. LED backlights also dim slowly with age and heat, and their life is often rated as the hours to half brightness, so a display that starts with headroom stays readable for longer.

Dimming matters as much as peak output. A screen bright enough for midday must dim low enough for night shifts and vehicle cabs after dark, ideally automatically through an ambient light sensor. Our guide to choosing a sunlight readable display covers brightness, bonding and contrast together.

We supply industrial and sunlight readable displays with the brightness, dimming and glass matched to where they will be installed, then configure and test each one before it ships.