Bedtime & wake-time calculator
Sleep runs in cycles of about 90 minutes. Waking up between cycles — not in the middle of one — is what makes a shorter night feel sharper than a longer one. Pick a direction and a target time.
Find my times
Suggested bedtimes
Each row is a full number of 90-minute cycles. The highlighted row (5–6 cycles) is the range most adults land in for 7.5–9 hours of sleep.
Tonight's wind-down timeline
Built from the bedtime you calculate above.
What's your chronotype?
Eight short questions on a framework used widely in sleep coaching: four rough chronotypes — Lion, Bear, Wolf and Dolphin — each with a different natural window for sleep, focus and food.
Sleep debt tracker
Enter how much you actually slept over the last seven nights against how much you need. The gap between the two doesn't vanish on its own — it's paid back with earlier nights or naps.
Last seven nights
Your balance
A short-term debt of 1–3 hours is common and recoverable with a couple of earlier nights or a daytime nap. Debt that keeps climbing week over week is the pattern worth changing, not any single rough night.
Your longer trend
Every night you edit above is saved on this device, so a real history builds up the more you use this.
Jet lag & shift-work adjuster
Your clock shifts by about an hour a day before it settles. This spreads a bedtime change over enough days to actually stick, and tells you which direction to chase light in.
The change
Day-by-day plan
Nap timer
The right nap length depends on what you're napping for. Too long, and you wake up from deep sleep groggy instead of refreshed.
Choose a nap
Set your alarm for
Caffeine cutoff calculator
Caffeine has a half-life of roughly five hours — a cup at 2pm still has a quarter of its punch left at 2am. This estimates how much is likely still in your system at bedtime.
Your last cup
Estimated caffeine left at bedtime
Wind-down checklist
Ten habits with the most consistent evidence behind them. Check off what you actually did today — your progress is saved on this device.