Sleep Calculator
Sleep cycles • Bedtime • Wake-up • Age recommendations • Sleep tips
I need to wake up at...
min
I'm going to sleep at...
min
📈 Sleep stages in one 90-min cycle
N1~10min
N2~30min
N3 (Deep)~30min
REM~20min
■ N1 Light
■ N2 Light
■ N3 Deep
■ REM Dream
👤 Recommended sleep by age (NSF guidelines)
💡 Sleep quality tips
Consistent schedule
Sleep and wake at the same time every day — even weekends
Dark room
Blackout curtains or eye mask — darkness triggers melatonin
Cool temperature
18–20°C (65–68°F) is optimal for deep sleep
No screens 1hr before
Blue light from phones suppresses melatonin production
Cut caffeine by 2pm
Caffeine has a 6-hour half-life and disrupts deep sleep
Exercise — but early
Regular exercise improves sleep quality. Avoid 3hrs before bed
ⓘ Sleep cycle durations vary by individual. These are estimates based on an average 90-minute cycle. Consult a doctor if you have persistent sleep issues.