Pevlika Browser Apps

Sleep Calculator

Plan enough time for sleep, allowing for the time you usually take to fall asleep.

Runs in your browser — nothing is uploaded
Plan from

—

How to use Sleep Calculator

  1. Choose a target wake time or bedtime.
  2. Set your estimated time to fall asleep.
  3. Compare the seven-, eight- and nine-hour planning windows in your device time zone.
Sources: NHLBI sleep stages and NIH healthy sleep.

Formula & assumptions

  • Based on NHLBI sleep-stage guidance and NIH adult sleep guidance.

Questions

Do sleep cycles last exactly 90 minutes?

No. NHLBI describes cycles around 80–100 minutes; timing varies across people and the night. A calculator cannot identify your sleep stage.

How much sleep should adults plan for?

NIH recommends about seven to nine hours for adults. Individual needs vary; these planning windows are not a diagnosis.

Online TimerCountdown timer, stopwatch with laps, countdown to a date and Pomodoro — with an alarm. World ClockLive clocks for cities around the world, with offsets from your time. Age CalculatorCalculate exact age in years, months and days, and the days until the next birthday. Date CalculatorCount the days between two dates, or add and subtract days, weeks, months or years.