Troubleshooting
Why does my screen keep dimming?
A handful of settings cause this, and they stack — fixing one doesn't always fix all of it. Here's each cause and its specific fix, or skip straight to the instant fix below.
Pick a duration and hit start.
Duration
The usual causes
Idle timeout (the most common one)
Every OS dims the display a short while before it locks, as a warning. This is a separate, shorter timer than the lock timer itself — so if your screen dims after, say, 90 seconds and locks at 2 minutes, that's one setting with two stages, not two separate problems. Adjust it under your display/power settings (see ourplatform-by-platform guide).
Battery saver / power-saving mode
Most laptops and phones shorten the idle timeout automatically when battery saver kicks in, on top of whatever you've manually set — plugging in (or disabling battery saver) often fixes dimming that only happens on battery.
Adaptive/automatic brightness
This is a different mechanism entirely — it changes brightness based on ambient light sensed by the camera/sensor, not on idle time. If your screen dims when you cover the sensor or move to a darker room (not after a period of inactivity), this is the cause, not idle timeout — turn it off in display settings if you'd rather control brightness manually.
A background app or browser extension
Less common, but some "system optimizer" or battery-management apps enforce their own aggressive dimming independent of OS settings. If you've ruled out the above and it's still happening, check what's running in the background.
The instant fix
If you just need the dimming to stop right now, for this one task, without digging through settings menus (or you're on a work laptop where you can't change them) — that's what the tool above does. Pick a duration, hit start, and it holds the display open directly, no setting changes involved.