Blue Light Filter Strength Calculator
Enter your screen habits to calculate optimal blue light filter strength for better sleep and reduced eye strain.
Time spent on devices 2-4 hrs before sleep
What percentage of blue light should I block?
Daytime (work/study): 20-30% - reduces eye strain without color distortion. Evening (2-3 hrs before bed): 60-80% - signals melatonin production. Night (1 hr before sleep): 90-100% (red-tinted glasses). Higher % = more sleep-friendly but worse color accuracy. Gamers/designers: Use 20-30% for balancd protection.
Do blue light glasses really work?
Yes, quality glasses with yellow/amber tints block 30-90% of blue light (400-495nm). Studes show 20-30% improvement in sleep quality, 15-25% reduction in eye strain, 10-15% improvement in melatonin production. Cheap clear glasses often block <10% (ineffective). Look for >50% block in 450-480nm range.
What is the best screen filter setting?
Night Shift (iOS): 70-80% warmth at night. f.lux: 3400K evening, 2700K night. Windows Night Light: 80-90% strength. Android Eye Comfort: Level 4-5. For daytime: 20-30% warmth. Too much yellow tint (50%+) during day distorts colors and reduces productivity.
How does blue light affect melatonin?
Blue light (especially 460nm) hits ipRGC cells in retina, signaling "daytime" to suprachiasmatic nucleus. This suppresses melatonin up to 50-85% for 1-3 hours after exposure. Even 30 minutes phone use at 90% brightness can delay sleep onset 45 minutes. 60-80% filter 2 hrs before bed restores 70-80% of natural melatonin.