Blue Light Screen Cutoff Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 28, 2026Blue Light Screen Cutoff Calculator
Trying to improve sleep onset? This calculator tells you exactly when to put screens away based on your target bedtime.
Screen Cutoff Time = Target Bedtime - Buffer Minutes
Example
Target bedtime of 10:30 PM, 90-minute buffer:
Stop screens by 21:00 (9:00 PM)
Why Screens Specifically Interfere With Sleep
Blue light exposure from phone, tablet, and computer screens in the hour or two before bed can suppress natural melatonin production and delay the body's internal sleep signal - unlike dim warm lighting, the blue-heavy spectrum of most screens mimics daylight, signaling wakefulness to the brain.
Why 60-90 Minutes Is a Common Starting Point
A 60-90 minute screen cutoff before bed is a commonly recommended starting point for improving sleep onset - some people find even a shorter buffer helpful, while switching devices to night mode or blue-light-filtering settings during this window is a common partial alternative when full cutoff isn't practical.