Sleep Calculator
Choose whether you want to wake up at a certain time or go to bed now, and get the best times based on full sleep cycles.
Times assume about 15 minutes to fall asleep. The best options (more sleep) are highlighted.
About sleep cycles
Waking up in the middle of a deep sleep cycle is what makes you feel groggy. By timing your sleep around complete 90-minute cycles, you’re more likely to wake up naturally and feel rested. This calculator works out those ideal times for you.
Frequently asked questions
How does the sleep calculator work?
Sleep happens in roughly 90-minute cycles. Waking at the end of a cycle (rather than mid-cycle) helps you feel refreshed. We also add about 15 minutes to fall asleep.
How many cycles should I aim for?
Most adults do best with 5–6 cycles (about 7.5–9 hours) of sleep per night.
Is this medical advice?
No — it’s a helpful guide based on average sleep cycles. Everyone is different.
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