Plan around sleep cycles
Sleep cycle calculator
Explore bedtime and wake-time options around complete sleep cycles, whether you are planning tomorrow or checking the clock right now.
Try the calculator
Wake time is saved separately from your bedtime.
Choose what you want to plan, then enter a time.
We’ll work backwards through complete sleep cycles.
Your target cycles
We'll show one shorter and one longer option.
Your recommendations
will appear here.
Choose 0 to 120 minutes.
Three ways to plan
Bedtime
Choose Bedtime when you know when you need to get up. The calculator works backwards to suggest bedtimes for the selected number of cycles. Readwhat time you should wake up if you are still choosing that time.
Wake
Choose Wake when you are ready to wind down. It works forward to show wake-time options that fit complete cycles.
Now
Choose Now for a quick check from the current time. This is useful when deciding whether to start winding down or set an alarm.
Cycle planning is a useful approximation
A 90-minute cycle is a convenient model, not a precise rule. Real sleep varies across people and nights, so compare the options with your schedule, responsibilities, and usual sleep needs.
Read how sleep cycles work for more context.
Need one focused answer? Visit thebedtime calculator.