When should you go to sleep?

If you went to sleep right now, when should you wake up to feel refreshed? Science says 5 to 6 sleep cycles a night is the sweet spot.

I have to wake up at…

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I will go to sleep at…

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Going to bed right this moment?

How much sleep do you need?

Age group Age range Recommended

The stages of sleep

Sleep patterns by age, in detail

Total hours needed is only part of the picture — how that sleep is spread across day and night changes a lot as we grow.

How to use this calculator

Are you getting enough sleep?

How the cycle changes across the night

Sources & further reading