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Sleep Calculator

Health
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Calculates optimal bedtimes and wake-up times based on sleep cycles. It helps you determine when to go to bed or wake up to feel most refreshed.

More tools:Health Calculators
How To Use

How to use this calculator

Start with your values, or try a preset.

Step 1

Enter Number of Sleep Cycles, Length of Sleep Cycle, Desired Wake-Up Hour (24-hour format), and Desired Wake-Up Minute in the units shown.

Step 2

Read Optimal Bedtime 1 (Minute), Optimal Bedtime 1, Total Sleep Time, Optimal Bedtime 2 (Minute), Optimal Bedtime 2, Total Sleep Time (Hours), Optimal Bedtime 3 (Minute), Optimal Bedtime 3, Optimal Bedtime 4 (Minute), and Optimal Bedtime 4 in the results panel. Results update as you change the inputs.

Step 3

Choose a preset to load an example, then adjust the values for your situation.

Worked Examples

Example calculations

See the inputs and their calculated results.

8 hours of sleep

Number of Sleep Cycles: 5 cycles; Length of Sleep Cycle: 90 minutes; Desired Wake-Up Hour (24-hour format): 7 hours; Desired Wake-Up Minute: 0 minutes

Optimal Bedtime 1 (Minute): 30 minutes; Optimal Bedtime 1: -1.5 hours; Total Sleep Time: 450 minutes; Optimal Bedtime 2 (Minute): 30 minutes; Optimal Bedtime 2: -2.5 hours; Total Sleep Time (Hours): 7.5 hours; Optimal Bedtime 3 (Minute): 30 minutes; Optimal Bedtime 3: -3.5 hours; Optimal Bedtime 4 (Minute): 30 minutes; Optimal Bedtime 4: -4.5 hours

6 hours of sleep

Number of Sleep Cycles: 4 cycles; Length of Sleep Cycle: 90 minutes; Desired Wake-Up Hour (24-hour format): 7 hours; Desired Wake-Up Minute: 0 minutes

Optimal Bedtime 1 (Minute): 0 minutes; Optimal Bedtime 1: 1 hours; Total Sleep Time: 360 minutes; Optimal Bedtime 2 (Minute): 0 minutes; Optimal Bedtime 2: 0 hours; Total Sleep Time (Hours): 6 hours; Optimal Bedtime 3 (Minute): 0 minutes; Optimal Bedtime 3: -1 hours; Optimal Bedtime 4 (Minute): 0 minutes; Optimal Bedtime 4: -2 hours

7.5 hours of sleep

Number of Sleep Cycles: 5 cycles; Length of Sleep Cycle: 90 minutes; Desired Wake-Up Hour (24-hour format): 7 hours; Desired Wake-Up Minute: 30 minutes

Optimal Bedtime 1 (Minute): 0 minutes; Optimal Bedtime 1: -0.5 hours; Total Sleep Time: 450 minutes; Optimal Bedtime 2 (Minute): 0 minutes; Optimal Bedtime 2: -1.5 hours; Total Sleep Time (Hours): 7.5 hours; Optimal Bedtime 3 (Minute): 0 minutes; Optimal Bedtime 3: -2.5 hours; Optimal Bedtime 4 (Minute): 0 minutes; Optimal Bedtime 4: -3.5 hours

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Important

Use the result as an estimate and confirm any medical decisions with a qualified professional.