Sleep Calculator
Calculate the best bedtime or wake time based on 90-minute sleep cycles.
Updated April 2026 · CalcFlow Editorial
Enter values above and click Calculate to see your results.
How to Use
- Select whether you want to know bedtime or wake time.
- Enter your target time.
- Click Calculate for optimal sleep times.
Formula
Bedtime = Wake Time - (90 min x Sleep Cycles) - 15 min fall-asleep time