Sleep Calculator: Perfect Sleep Time

HOW MUCH SLEEP DO WE REALLY NEED?

HOW MUCH SLEEP DO WE REALLY NEED?

This is the precise time to go to bed if you want to wake feeling refreshed tomorrow

Each cycle lasts roughly 90 minutes, and each you should pass through five or six of them. "Waking up mid-cycle can leave you feeling grumpy and tired," they warn: "rising in between phases will help you to start the day with a smile on your face."

Using the calculator, simply enter the time you need to wake up in the morning, and it will offer a selection of optimal times to go to bed.