Loading…
Loading…
SleepCycle
Sleep happens in 90-minute cycles. This tool tells you when to sleep (or wake) to land at the end of one.
Waking mid-cycle (especially during deep sleep) feels groggy. Waking between cycles, during a lighter sleep stage, feels naturally easy — that's why 7.5 hours can beat 8 hours.
Daily energy expenditure with personalised macro splits.
OpenBody mass index with healthy-range guidance.
OpenUS Navy circumference method for body fat percentage.
OpenDaily hydration target based on weight, activity, and climate.
Open3 cycles · 4.5h
2:00 AM
Be asleep by this time
4 cycles · 6h
12:30 AM
Be asleep by this time
5 cycles · 7.5h
11:00 PM
Be asleep by this time
6 cycles · 9h
9:30 PM
Be asleep by this time
Most adults wake feeling best at the end of a sleep cycle — typically after 5 or 6 cycles (7.5h or 9h).
What you entered
Start from your target wake-up time
6:30 AM= 6:30 AMEach sleep cycle runs about 90 minutes
5–6 cycles is a typical full night= 90 min/cycleCount 90-minute cycles backward
−90 min × [3, 4, 5, 6] cycles= 3×: 2:00 AM; 4×: 12:30 AM; 5×: 11:00 PM; 6×: 9:30 PMResult
5-cycle target: 11:00 PM
Sleep happens in ~90-minute cycles, and waking near the end of one (rather than mid-cycle) tends to feel less groggy — these are the times that land you at the end of a full cycle count.