Do you know much sleep your child needs? If the answer is no, you’re not alone. And if you answered yes—well, you might be surprised. According to a 2016 survey, 1 in 4 parents think their children need less than the recommended amount of sleep, while another 1 in 5 think their kids need more than the recommended amount. That’s a problem, because adequate sleep is essential for optimal growth and development. Here’s how much sleep your child needs at each stage of childhood. Newborns: 16 to 18 hours a day From birth to about 4 months of age, infants sleep about 16 to 18 hours per 24 hours. But that sleep is erratic. It’s not uncommon for a newborn to sleep just an hour or two at a time, and most babies don’t establish regular sleep cycles until about six months of age. Until then, hold on as best you can. (Yes, that means napping when your baby sleeps, as often as possible.) Infants: 12 to 16 hours a day Babies between the ages of four and 12 months of age should sleep between 12 and 16 hours per day, counting naps. But babies’ sleep patterns change greatly between four months and one year. At four months, most babies are taking three or more naps a day. By a year, most babies are down to two naps a day. And while most babies have settled into a regular sleep schedule by six months, that “regular schedule” will change throughout the year as your baby experiences teething and separation anxiety. Putting your baby to bed while drowsy, rather than rocking until he is fully asleep, can help your child establish good sleep habits—and the ability to fall asleep independently. If your baby fusses during the night, try waiting a few minutes before you respond to see if he settles back down. Toddlers: 11 to 14 hours a day Toddlers are notoriously difficult to put to bed, in part because they’re so busy exploring the world. Yet sleep is essential to learning and skill development. A child who doesn’t get enough sleep may have trouble focusing, solving problems, and controlling their emotions—and those skills are already tough enough for toddlers! Help your child get the sleep he needs by establishing a consistent bedtime schedule. If you have to be out the door by 7 a.m. each day, start the evening routine no later than 6:30 or 7 p.m. That allows for 20 or 30 minutes to wash up, read books, and tuck in, and sets the stage for approximately 11 hours of nighttime sleep. Add in a daytime nap of an hour or two, and your toddler is set. Preschoolers: 10 to 13 hours a day Did you know lack of sleep increases susceptibility to illness? In other words, if you want your child to stay healthy, make sure she gets plenty of sleep. It can be hard to tell when a young child is tired because unlike adults, children become more active when they get sleepy. If your child is bouncing off walls as the evening wears on, there’s a good chance she’s overtired. Try putting your child to bed a half-hour or so earlier the next night; ideally, you want to start bedtime before the wiggles set in. Once you discover your child’s optimal bedtime, stick to it, even on weekends. Consistency will make bedtime and mornings easier all around, and increase the likelihood of your child getting enough sleep. School-age kids: 9 to 12 hours a day According to a 2012 study, 64% of school-age children go to bed later than 9 p.m. That’s not ideal, because kids between the ages of 6 and 10 need 9 to 12 hours of sleep per night. And while it’s technically possible to squeeze in 10 hours of rest between 9 p.m. and 7 a.m., that’s not usually what happens. The same study found only about half of the boys surveyed got the recommended amount of sleep each night. One way to encourage sleep: remind kids that sleep triggers the release of growth hormones. Another way: ban digital devices from the bedroom. Better yet: power down cell phones, computer screens and TVs at least 30 minutes before bed. Teens: 8 to 10 hours a day As children enter the teen years, their internal body clocks shift. They’re prone to staying up late and sleeping in—but unfortunately, most teens don’t have the option of sleeping until they’re well-rested. School schedules typically require them to be awake hours before their internal alarms jangle. No wonder so many teens doze through first hour classes! But teens who are sleep deficient have more problems getting along with others and are prone to anger and impulsiveness. They’re more likely to be depressed and to lack motivation, and each hour of lost sleep increases teens’ risk of obesity, which in turn increases their risk of diabetes and heart disease. One of the best things you can do to encourage healthy sleep habits in your teens: set a good example. Power down your devices well before bedtime. Schedule some time to unwind before bed, and show your teen, through word and deed, that a good night’s sleep is a priority.