4 Steps to Answer the “How Much Sleep Do I Need?”

Forget the age-old eight-hours-a-night rec. Here’s how to determine the optimal amount of sleep your body needs—down to the exact minute.

Want to sharpen your memory, clear your head, and maintain a healthy weight? Studies suggest it all comes down to catching more Z’s. And while you’re (hopefully) giving it your best effort to secure eight hours a night (right smack in the middle of the seven to nine hours recommended by the National Sleep Foundation), the optimal amount of sleep needed varies from person to person.

“Approximately 70 percent of the population requires between six and nine hours a night to feel well-rested and refreshed daily,” says Shelby Harris, PsyD, director of behavioral sleep medicine at the Sleep-Wake Disorders Center at Montefiore Medical Center. That’s a pretty big range, and while researchers haven’t nailed down all the reasons you require eight hours while your best friend feels fine on six, genetics play a role, Harris says.

Since you can’t change your sleep genes, might as well find out what they say your body needs to answer the “how much sleep do I need?” question once and for all (you’ll thank us later). By zeroing in on your ideal number of minutes spent sleeping each night and consistently hitting that target, everything from your motor skills to your mood stand to benefit, Harris says. “Sleep is key, and not getting enough is a detriment to your health,” she says.

Here, Harris shares four steps to determine just how much shut-eye you really need.

1. Have a weeklong summer vacation or staycation coming up? Any stretch of seven days when you’re free from the blaring 6 o’clock alarm will work. Consider this your chance to take the test, and mark the seven days on your calendar.
2. Shoot to go to sleep at the same time every night. Note what time you wake up each morning naturally, without the help of an alarm.
3. Calculate how much you sleep on nights 4, 5, and 6 (a tracker, like Fitbit, can help you get it down to the minute). Add them together. “Don’t factor in the first three nights because you’re likely a bit sleep deprived from the week before and catching up,” Harris says.
4. Divide that number by 3.

Boom: The result is the approximate number of minutes of sleep that’s right for your body and gives you a solid answer to “how much sleep do I need?” Once you snap back to post-vacation reality, count back from the time your alarm needs to go off each morning to determine your bedtime. Chances are you’ll feel better in the morning.