Sleep time Calculator: Find Your Perfect
Bedtime for Better Sleep

Sleep timing matters as much as sleep length. Our calculator uses 90-minute sleep cycles to find your perfect bedtime or wake-up time.

I need to wake up at…

Based on 90-min sleep cycles + 14 min to fall asleep

What is a sleep cycle?

While you sleep, your brain cycles through four distinct stages — roughly every 90 minutes. Waking up at the end of a cycle (rather than mid-cycle) is why some alarms leave you refreshed and others leave you groggy.

Stage 1N1 — Light Sleep1–5 min

The transition between wakefulness and sleep. Muscles begin to relax and you may experience hypnic jerks.

Stage 2N2 — Light Sleep10–25 min

Body temperature drops, heart rate slows. Sleep spindles appear — bursts of brain activity that help consolidate memory.

Stage 3N3 — Deep Sleep20–40 min

The most restorative stage. Growth hormone is released, tissues repair, and your immune system strengthens.

Stage 4REM Sleep10–60 min

Rapid Eye Movement sleep — where most dreaming occurs. Critical for learning, memory, and emotional processing.

One complete sleep cycle ≈ 90 minutes

How much sleep do you need?

The right amount varies by age. Most adults need 5–6 full cycles, which equals 7½ to 9 hours.

Newborns (0–3 months)14–17 hours
Infants (4–11 months)12–15 hours
Toddlers (1–2 years)11–14 hours
School-age (6–13)9–11 hours
Teenagers (14–17)8–10 hours
Adults (18–64)7–9 hours
Older Adults (65+)7–8 hours

Tips for better sleep

  • Stick to a consistent sleep schedule — even on weekends.
  • Keep your bedroom cool, dark, and quiet.
  • Avoid screens 30–60 minutes before bed.
  • Avoid caffeine after 2 PM.
  • Get natural light exposure in the morning.
  • A warm shower before bed helps your core temperature drop faster.