How do I use the Sleep Calculator?

Pick whether you want to know when to go to bed, or when to wake up. Enter your target wake time or when you're planning to sleep. Choose from options based on how many cycles you want - 5 or 6 cycles (7.5-9 hours) is usually ideal.

Is the Sleep Calculator free?

Yes, the Sleep Calculator on ToolHaven is completely free to use. No signup or registration is required.

Sleep Calculator

Sleep works in 90-minute cycles, and waking up mid-cycle is why you feel groggy even after 8 hours. Enter your wake time or bedtime and this shows you the ideal times to sleep or wake up so you finish a full cycle.

Tip

Aim for 5–6 sleep cycles (7.5–9 hours). This planner adds a configurable fall-asleep time.

Wake-up time

Fall asleep (minutes)

00:46

4 cycles (6 hours)

Bed

23:16

5 cycles (7.5 hours)

Bed

21:46

6 cycles (9 hours)

Bed

20:16

7 cycles (10.5 hours)

Bed

How to use

Pick whether you want to know when to go to bed, or when to wake up.
Enter your target wake time or when you're planning to sleep.
Choose from options based on how many cycles you want - 5 or 6 cycles (7.5-9 hours) is usually ideal.

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