sleep-calculatorClassic tool
Sleep Calculator
Calculate sleep or wake times based on 90 minute sleep cycles.
Use this tool when you want a quick reference for when to go to bed or when to wake up without doing the math yourself. It is useful for workdays, study routines, naps and travel planning.
Enter a time, choose the calculation mode and get practical suggestions based on 90 minute cycles.
Use clear inputs to get a more useful result.