Wake up sharp, not groggy.
Plan your bedtime or wake time around complete 90-minute sleep cycles.
Sleep schedule
Sleep cycles run ~90 min. Waking between cycles feels less groggy than waking mid-cycle. Recommended for your age: 7–9 hours.
- 2:15 AM3 cycles · 4.5 h
- 12:45 AM4 cycles · 6 h
- 11:15 PM5 cycles · 7.5 h★ In recommended range
- 9:45 PM6 cycles · 9 h★ In recommended range
Good to know
Why 90-minute cycles?+
A full sleep cycle — light → deep → REM — runs around 90 minutes for most adults. Waking at the end of a cycle feels sharper than being jolted mid-cycle. The multiples we show target cycle boundaries.
How much sleep do I really need?+
Adults 18–64 need 7–9 hours (5–6 cycles). Teenagers 8–10 hours (5–7 cycles). Seniors 65+ 7–8 hours (5 cycles). Under 7 hours is associated with worse health outcomes across the board.
What about sleep latency?+
Sleep latency is the time from lights-off to actually being asleep — usually 10–20 minutes. We subtract it from your target bedtime so the math works out to real wake-up feelings.
