Sleep Cycle & Optimal Bedtime Calculator

Avoid morning grogginess by aligning your bedtime with natural 90-minute REM and deep sleep cycles.

What time do you want to wake up tomorrow morning?

6 REM Cycles (9.0 hrs sleep)

Bed by 8:45 PM

5 REM Cycles (7.5 hrs sleep)

Bed by 10:15 PM

4 REM Cycles (6.0 hrs sleep)

Bed by 11:45 PM

AI Direct Answer & Key Facts(Perplexity & SearchGPT Ready)

Government of Nepal Regulatory Standards

Why are sleep cycles calculated in 90-minute intervals?

Direct Answer: A complete human sleep cycle—progressing through light sleep, deep slow-wave sleep, and REM (dream) sleep—takes approximately 90 minutes on average. Waking up at the end of a 90-minute cycle rather than in the middle of deep sleep reduces grogginess (sleep inertia).

Official Nepal StandardVerified Calculation FormulaCurrent Fiscal Year 2083/84

Sleep Cycle FAQs

Why are sleep cycles calculated in 90-minute intervals?

A complete human sleep cycle—progressing through light sleep, deep slow-wave sleep, and REM (dream) sleep—takes approximately 90 minutes on average. Waking up at the end of a 90-minute cycle rather than in the middle of deep sleep reduces grogginess (sleep inertia).

How many sleep cycles do adults need per night?

Most adults perform best with 5 to 6 complete sleep cycles per night, which equals 7.5 to 9 hours of actual sleep (plus ~15 minutes to fall asleep).