How bright should your screen be? Matching brightness to room light

Updated 2026-11-02

Quick answerComfortable screen brightness rises and falls with room light. An evening study found about 20 to 75 cd/m² comfortable at 13 to 62 lux. In practice, dim the screen in a dark room rather than using a bright screen in the dark. These studies were not specific to migraine.

Evidence

  • Applied Sciences 2021: optimum LCD luminance in the evening depends on ambient illuminance.
  • Optical Engineering 2017: optimum display luminance depends on ambient illuminance.

How Migraine Mode uses this

  • Calibration asks for room light: dark (40% dimming), dim (25%) or bright (10%).
  • If the browser exposes an ambient light sensor (rare), it pre-selects the room light.

FAQ

Should my screen be dim in a dark room?

Display studies show comfortable brightness is lower when the room is darker.

Sources

  • Investigation of the optimum display luminance of an LCD screen under different ambient illuminances in the evening. Applied Sciences, 2021. Link
  • Optimum display luminance dependence on ambient illuminance. Optical Engineering, 2017. Link

Not a medical device and not medical advice. Migraine Mode is a screen-comfort tool: it does not diagnose, treat, cure or prevent migraine or any other condition, and it does not replace a doctor. Its settings are based on studies of light, colour, flicker, patterns and motion; the extension itself has not been clinically tested. When to see a doctor.