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Sleep Calculator

Estimate suggested bedtime from wake or bedtime minute, sleep cycles, sleep cycle length with the Sleep Calculator.

Choose a sleep workflowPlan bedtime from cycles or measure overnight sleep length.
2 options
SUGGESTED BEDTIME21:45

Suggested 24-hour bedtime; wake time − cycles × cycle length − sleep latency. Only inputs needed by this operation are shown.

Estimate based on the values shown
MethodCycle planning subtracts cycle time and sleep latency; overnight duration wraps at 24 hours.

Before you use the result

Check the entered units and assumptions before using the result for purchasing, construction, engineering, or safety decisions.

Sources

CALCULATOR GUIDE

How to use the Sleep Calculator

Estimate suggested bedtime from wake or bedtime minute, sleep cycles, sleep cycle length with the Sleep Calculator. It includes Sleep Cycle, Sleep Length workflows, so choose the one that matches the values you actually know. Use it to check a practical estimate, paying close attention to the selected units and assumptions.

Step by step

  1. For the Sleep, enter wake or bedtime minute, sleep cycles, sleep cycle length, time to fall asleep, sleep start minute. Keep each value in the unit displayed beside its field.
  2. Review the selected Sleep workflow and inputs, then read suggested bedtime in the result panel.
  3. Change one Sleep assumption at a time to compare scenarios. Use Reset to restore this tool's worked example values.

How the calculation works

Cycle planning subtracts cycle time and sleep latency; overnight duration wraps at 24 hours.

Worked example

In the Sleep worked example, wake or bedtime minute 420, sleep cycles 6, sleep cycle length 90 min, time to fall asleep 15 min produces suggested bedtime of 21:45. Suggested 24-hour bedtime. Review the displayed units before comparing the result.

Understanding the result

The Sleep reports suggested bedtime. Use it to check a practical estimate, paying close attention to the selected units and assumptions. Check the entered units and assumptions before using the result for purchasing, construction, engineering, or safety decisions.

How to check the answer

Check the Sleep result by reversing the conversion or recomputing suggested bedtime from wake or bedtime minute, sleep cycles, sleep cycle length. For construction, electrical, weather, or purchasing decisions, compare the result with the applicable specification or professional guidance.

Common questions

What does the Sleep calculate?

Estimate suggested bedtime from wake or bedtime minute, sleep cycles, sleep cycle length with the Sleep Calculator.

Which Sleep inputs have the biggest effect?

suggested bedtime responds directly to wake or bedtime minute, sleep cycles, sleep cycle length, time to fall asleep, sleep start minute. Change one input while holding the others constant to see its effect.

Is the Sleep result exact?

Check the entered units and assumptions before using the result for purchasing, construction, engineering, or safety decisions. Recheck wake or bedtime minute, sleep cycles, sleep cycle length and use suggested bedtime only for a decision where that level of precision is appropriate.

Formula tests, limits, sources, and guide registry updated September 1, 2026.
INTERPRET THE RESULTRead the other guideCheck assumptions, limitations and comparison methods →