Sleep Cycle Calculator

Plan bedtimes or wake-up times around 90-minute sleep cycles.

Wake-up time

15 minutes to fall asleep is included.

Suggested bedtimes

4 cycles（6 h）00:15

5 cycles（7.5 h）previous day22:45

6 cycles（9 h）previous day21:15

Note: sleep cycles are estimates and vary between individuals; actual time to fall asleep also affects results.

Related Tools

Find your exact age in years, months and days, plus a countdown to your next birthday.

Split the bill and calculate tips, totals and per-person amounts in seconds.

Compare equal-payment and equal-principal loans — monthly payment and total interest instantly.

See how your money grows with compound interest — principal, rate and years is all you need.

Estimate monthly income tax and take-home pay with custom social insurance deductions.

Convert discount rates to final prices and savings, including spend-and-save deals.