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 may differ from measured light output. If the number looks wrong, check the active brightness controller, preset and any manual nits overrides.

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. A missing row means the app has no value to report.

These limits describe the display’s reported capabilities. Current EDR instead describes HDR headroom relative to SDR. Neither measures the current picture.

If you change the monitor’s peak-brightness mode, check whether the reported values change as well. Use a measuring instrument 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 value of 1,600 nits does not mean the whole desktop can sustain that brightness. Automatic brightness and the active control path can also change the available range. The maximum also depends on the Mac model and 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 screens by eye or using another monitor’s advertised peak cannot give you 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. To request a specific level, use a nits-based adjustment if the active controller supports it. The requested or reported value can still differ from measured panel brightness.

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. This information helps identify which part of the calculation needs checking.