Find bedtimes or wake times that align with complete 90-minute sleep cycles, so you wake between cycles rather than mid-cycle when you feel groggiest.
How it works
- Select whether you want to calculate a wake-up time or a bedtime.
- Enter your desired sleep or wake hour.
- See a list of optimized alarm times that prevent you from waking up mid-cycle.
Frequently asked questions
Why 90 minutes?
A full sleep cycle (light, deep, REM) averages about 90 minutes. Waking at a cycle's end feels more refreshing than waking mid-deep-sleep.
How many cycles do I need?
Most adults do best with 5 to 6 cycles (7.5 to 9 hours).
Is 15 minutes to fall asleep accurate?
It is a common average; adjust mentally if you usually drift off faster or slower.
Should I aim for a specific bedtime?
Consistency matters more than the exact hour — going to bed and waking at the same time each day stabilises your circadian rhythm more than any single sleep target.