Sleep Calculator
Time your sleep in complete 90-minute cycles so you're more likely to wake up feeling rested, not mid-cycle.
Plan around
Recommended times (full 90-minute cycles):
| Cycles | Total sleep | Time |
|---|
Why 90-minute cycles?
Sleep moves through light, deep, and REM stages in cycles that average about 90 minutes. Waking up at the end of a cycle (rather than in the middle of deep sleep) tends to feel more refreshing. Most adults do well with 5–6 full cycles (7.5–9 hours) per night.