Waking up mid-cycle can leave you feeling groggy, even after enough total sleep. This calculator uses the average 90-minute sleep cycle to suggest optimal bed or wake times.
Waking up mid-cycle can leave you feeling groggy, even after enough total sleep. This calculator uses the average 90-minute sleep cycle to suggest optimal bed or wake times. This calculator draws on peer-reviewed, industry-standard formulas used by fitness professionals, dietitians and clinicians worldwide, translated into a fast, easy-to-use browser tool.
Tracking metrics like this over time — rather than relying on a single reading — gives you a much clearer picture of trends in your health and fitness journey. Use this tool regularly alongside our other calculators for a fuller picture of your overall wellbeing.
Sleep happens in cycles of roughly 90 minutes each, moving through light sleep, deep sleep, and REM. Waking up at the end of a cycle (rather than mid-cycle) generally feels less groggy.
Most adults need 5-6 complete cycles (7.5-9 hours) per night for optimal physical and mental recovery.
Yes, we factor in an average of 14 minutes to fall asleep, based on sleep research, when calculating suggested times.