Most babies need 9 to 12 hours of nighttime sleep, but the exact number depends on age. Newborns don’t follow a day-night pattern at all, sleeping in short bursts around the clock, while older infants gradually consolidate more of their sleep into nighttime hours. Here’s what to expect at each stage and what affects how long your baby actually stays asleep.
Total Sleep Needs by Age
Newborns (0 to 3 months) sleep 16 to 18 hours per day, but only 1 to 2 hours at a time. There’s no real distinction between “night sleep” and “day sleep” at this age because their internal clock hasn’t developed yet. The American Academy of Sleep Medicine doesn’t even issue a specific sleep recommendation for babies under 4 months because sleep patterns vary so widely.
Infants 4 to 12 months old need 12 to 16 total hours of sleep per day, including naps. As naps shorten with age, nighttime sleep stretches longer. By around 6 months, many babies are getting 10 to 12 hours overnight (though not necessarily uninterrupted). By 12 months, most babies take two naps totaling 2 to 3 hours and sleep 11 to 12 hours at night.
When Babies Start Sleeping Through the Night
“Sleeping through the night” typically means a stretch of 6 to 8 hours without waking, and most babies reach this milestone around 3 months old. That said, 6 to 8 hours starting at 7 or 8 p.m. means your baby might still be awake at 2 or 3 a.m. True adult-style sleep, where a baby sleeps from bedtime to morning, usually comes later, often between 6 and 12 months.
The reason newborns can’t do this is biological. Babies are born without a functioning internal clock. They don’t produce melatonin, the hormone that signals nighttime drowsiness, and they lack a stable sleep-wake cycle. Melatonin production typically begins around 6 to 8 weeks of age, with a recognizable day-night pattern emerging by about 2 months. One case study found that an infant exposed primarily to natural light developed nighttime sleep onset aligned with sunset by day 60.
Night Feedings and Sleep Interruptions
Even when babies are capable of longer stretches, hunger pulls them awake. The number of nighttime feedings drops steadily over the first year:
- 0 to 2 months: 3 to 5 feedings per night (breastfed) or 2 to 4 (formula-fed)
- 3 to 4 months: 3 to 4 feedings (breastfed) or 2 to 3 (formula-fed)
- 5 to 6 months: 1 to 3 feedings (breastfed) or 1 to 2 (formula-fed)
- 7 to 9 months: 0 to 3 feedings (breastfed) or 0 to 1 (formula-fed)
- 10 to 12 months: 0 to 2 feedings (breastfed) or 0 to 1 (formula-fed)
Breastfed babies tend to wake more often because breast milk digests faster than formula. This is normal and doesn’t mean anything is wrong with your milk supply or your baby’s sleep. By 7 to 9 months, many formula-fed babies can go the entire night without eating, while breastfed babies may still need one or two feeds.
Why Sleep Can Suddenly Get Worse
Sleep regressions are periods where a baby who was sleeping well suddenly starts waking more often or fighting bedtime. The most well-known one hits around 4 months, when a baby’s sleep cycles mature and begin cycling between light and deep sleep the way adults do. Each time they enter light sleep, they’re more likely to wake up fully.
Other common triggers include separation anxiety (which peaks around 9 months), teething pain, growth spurts that increase hunger, learning new physical skills like rolling over or pulling up, illness, and changes in routine like travel or starting daycare. These regressions are temporary, usually lasting 1 to 4 weeks, and they don’t mean your baby has lost the ability to sleep well.
How Naps Affect Nighttime Sleep
A common instinct is to cut naps so your baby sleeps longer at night. Research suggests the opposite is often true. A study tracking infants’ daytime and nighttime sleep found that longer daytime naps were associated with less light (restless) sleep at night and better cognitive performance, including faster visual attention. Babies who nap well tend to sleep more deeply overnight, not less.
The key is timing. Naps that run too late in the afternoon can push bedtime later, but eliminating naps or cutting them short usually leads to overtiredness, which makes nighttime sleep worse, not better.
Signs Your Baby Isn’t Getting Enough Sleep
Babies can’t tell you they’re tired, but their bodies give clear signals. Early signs include yawning, droopy eyelids, rubbing their eyes, pulling on their ears, and staring off into the distance. You might also notice them turning away from stimulation, like losing interest in a toy, the bottle, or even your face.
When a baby pushes past tired into overtired, the signs shift. Overtired babies often cry louder and more frantically than usual, become extremely clingy, and may even sweat more than normal. That sweating happens because the stress hormone cortisol surges when a baby is sleep-deprived, and cortisol also triggers a rush of adrenaline that can make an exhausted baby seem wired instead of drowsy. This is why an overtired baby can be paradoxically harder to put to sleep. Catching those early drowsy cues and starting the bedtime routine before overtiredness sets in makes a real difference.
Putting the Numbers in Perspective
The recommended ranges are guidelines, not rigid rules. Some 6-month-olds sleep 10 hours at night and thrive. Others need closer to 12. What matters more than hitting an exact number is whether your baby wakes up reasonably content, is alert and engaged during awake periods, and is gaining weight and meeting developmental milestones on schedule. If your baby consistently falls well outside the expected range for their age, or if sleep problems are paired with excessive fussiness, difficulty feeding, or breathing irregularities during sleep, that’s worth raising with your pediatrician.