Why does BetterDisplay’s nits value differ from the brightness I expect?

A displayed nits value can come from controller reports, known display data or a calculated estimate. It is not always a measurement of the light currently reaching your eyes. Check the active brightness controller, preset and any manual nits overrides before treating a surprising number as a panel fault.

To inspect reported HDR limits, open Settings > Displays > [display] > Display Information… and look under Capabilities. Where data is available, Minimum HDR luminance, Maximum average HDR luminance and Peak luminance report values in nits. A supported Apple display can also supply a peak value from its default Apple Display Preset. Missing rows mean the relevant data is unavailable, not that the display produces zero light.

These reported limits are distinct from Current EDR, which describes relative HDR headroom, and from a measurement of the current picture. Changing a monitor’s own peak-brightness mode does not by itself prove that its reported data changed. Compare the reported values and use measurements when actual luminance matters.

Peak luminance is also different from sustained full-screen luminance. For example, Apple specifies 1,000 nits sustained full-screen XDR brightness and 1,600 nits peak HDR brightness for the 16-inch MacBook Pro introduced in November 2023. A slider reaching 1,600 nits does not establish that the entire desktop will sustain that measured brightness. Automatic brightness and the active control path can also change the available range. Do not apply one observed ceiling to every Mac model or preset.

Open Settings > Displays > [display] > General Settings > Configure Brightness Nits Ranges…. Review the hardware minimum and maximum and, where available, the HDR/SDR anchors. Clearing an override restores its automatic basis. Switching off Manual nits range configuration ignores the saved overrides without deleting them.

Use reliable display data or measurements when supplying your own anchors. Comparing two screens by eye, or comparing a screen with another monitor's advertised peak brightness, does not establish an exact replacement value. HDR content, the active preset and automatic brightness can make comparisons misleading.

If you want these estimates to drive another screen, follow Match brightness across different monitors. It checks the range information before comparing the displays at several brightness levels.

On supported Apple controllers, manual anchors can recalibrate reported nits and conversion from requested nits values. These settings can therefore change nits-based brightness matching as well as the displayed number. Entering a larger maximum does not increase the panel's capabilities.

Equal brightness-percentage steps do not necessarily produce equal steps in nits. For direct built-in XDR control, the brightness range uses a curved mapping, so repeated percentage changes can show uneven nits increments. The displayed values are not random. When you need a specific level, use an available nits-based adjustment supported by the active controller, and distinguish its requested or reported value from a measurement of the panel.

If a reading still appears wrong, record the active controller, preset, manual anchors and automatic-brightness state alongside the reading. See brightness nits ranges for the meaning and limits of each field. A specific incorrect reading needs that evidence. There is no universal correction factor.