№ 47
What Time Should a Baby Go to Bed? Count Back From Wake-Up
The right bedtime is the one that counts back from your child’s wake-up time. Take the hours of sleep they need across a day for their age, subtract the hours they already nap, and count the rest back from the time they actually wake. That gives you the time they should be asleep. For some babies it lands at 7pm. For plenty of others it’s 7:30, 8 or 8:30, and that’s fine. Then let the mornings tell you whether the number is right.
Why 7pm became the default
Seven o’clock is a good round number, and round numbers travel. It turns up in sleep charts and baby-group advice alike. When I worked as a buyer for a big-box chain, the products that sold best were the one-size ones, because nobody had to measure anything to buy them. A fixed bedtime is the one-size version of sleep. It fits the child who wakes at 6, sleeps two hours in the day and needs 13 hours in total. It doesn’t fit the child who wakes at 7:30, or the one who still naps three hours.
What actually sets a bedtime is a sum, and two of its three parts can only be measured in your own house.
The one rule: count back from the wake-up
Bedtime = wake-up time − (daily sleep need − daytime sleep)
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Find the daily sleep need for your child’s age. The American Academy of Sleep Medicine’s consensus statement on sleep for children gives these ranges, all “per 24 hours”:
- “Infants 4 months to 12 months should sleep 12 to 16 hours per 24 hours (including naps)”
- “Children 1 to 2 years of age should sleep 11 to 14 hours per 24 hours (including naps)”
- “Children 3 to 5 years of age should sleep 10 to 13 hours per 24 hours (including naps)”
- “Children 6 to 12 years of age should sleep 9 to 12 hours per 24 hours”
Nemours KidsHealth’s page on how much sleep kids need gives the same ranges and adds 14 to 17 hours for babies up to 3 months. The AASM deliberately leaves out babies under four months, “due to the wide range of normal variation in duration and patterns of sleep.” So don’t try to set a clock bedtime for a newborn; what’s normal in those early weeks is in what normal infant sleep looks like. (That post uses the National Sleep Foundation’s slightly lower figures for babies.)
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Start in the middle of the range. You’ll adjust from there.
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Subtract what they already sleep in the day. Use your child’s real naps from the last few days, not the naps a chart says they should take.
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Count the remainder back from the time they actually wake. Use the wake-up you get on a normal weekday, not the one you’d like.
The answer is the time they should be asleep, not the time the routine starts. Lights-out comes a little earlier. KidsHealth suggests giving children a heads-up “30 minutes and then 10 minutes beforehand”, and a short routine like the four-step one fits inside that half hour. How a baby goes down is a separate question, covered in drowsy but awake.
A worked table
These are example children, not norms.
| Child | Wakes at | Day sleep | Daily aim (mid-range) | Night sleep needed | Asleep by |
|---|---|---|---|---|---|
| 9 months, two naps | 6:00 am | 3 h | 14 h | 11 h | 7:00 pm |
| 18 months, one nap | 7:00 am | 2 h | 12.5 h | 10.5 h | 8:30 pm |
| 2½ years, one nap | 6:30 am | 1.5 h | 12.5 h | 11 h | 7:30 pm |
| 4 years, no nap | 7:00 am | none | 11.5 h | 11.5 h | 7:30 pm |
| 6 years, no nap | 7:00 am | none | 10.5 h | 10.5 h | 8:30 pm |
Only one of the five comes out at 7pm. Put the 18-month-old to bed at 7 and you’re asking for 12 hours of night sleep on top of a two-hour nap, which is 14 in total, the very top of the range.
Two numbers in that sum change as children grow: naps shrink and the daily need falls. So the bedtime should be recalculated at every nap change.
When an earlier bedtime does help
An earlier bedtime is the right move when a child is short on sleep. KidsHealth lists what that looks like: a child who isn’t getting enough sleep may “fall asleep during the day”, “be hyperactive (especially younger children)” or “be cranky, whiny, irritable, or moody”. That hyperactive one fools people. A child who is wild at 7:45 can look like they aren’t tired, when really they’re past it.
Signs that bedtime is too late for the sum:
- they fall asleep in the car or the stroller at times they never used to;
- the hour before bed is the worst hour of the day;
- they wake grumpy and stay grumpy.
Betteroo’s guide to a two-day reset for an overtired baby suggests moving bedtime “30 to 60 minutes earlier than usual” and says that “most babies come back to baseline within two or three days”. It also says babies whose bedtime keeps drifting later “do not sleep in to compensate”. In practice that means a temporary earlier bedtime, not a new permanent one. Once the child is rested, go back to the sum.
When an earlier bedtime backfires
The same arithmetic run the other way explains most early waking. A four-year-old who needs about 11 hours and is asleep by 6:30pm has had all 11 by 5:30am. They aren’t waking early. They’re waking full.
Craig Canapari, a pediatrician at Yale-New Haven Children’s Hospital who treats children with sleep and breathing problems, makes the same distinction in his guide to early morning awakenings. He writes that “some children naturally wake up between 5:30-6:30 AM”, and that schedule changes “tend to work best if your child is getting enough sleep in a twenty-four hour period”. His test for enough sleep has two parts: sleep tracked over a few days falls in the normal range, and “when they wake up in the morning, they are happy and in a good mood.” For a rested child who still wakes early, his fix is a later bedtime, moved “by say 10 minutes a day with the goal of moving bedtime later by 30-60 minutes”, and then a week or two of waiting.
Betteroo’s guide to the usual reasons a baby is up before six puts overtiredness first, but it lists the other side too: “too much day sleep”, and a last stretch awake that is so short “your baby is not tired enough for a full night.”
So the mood test chooses between the two fixes:
| In the morning they are… | Total sleep is… | Bedtime probably needs to… |
|---|---|---|
| grumpy, and flagging by mid-morning | below the range | come earlier, for a few days |
| cheerful, ready to start | in the range | stay put, or move later in 10-minute steps |
The minimalist version
Everything above needs no equipment. You need your child’s real wake-up time, a three-day note of their naps, the range for their age and some subtraction. Canapari suggests tracking “two typical weekdays and one weekend” and taking the average. Do that once and bedtime stops being a nightly negotiation.
Change one thing at a time, and give it a week. If you’ve also been testing an earlier dinner, let that settle first, or you won’t know which change did the work.
FAQ: choosing a bedtime
Is 7pm too early for a baby? Not always. It suits a baby who wakes at 6 and naps about three hours. It’s too early for a child who wakes at 7:30 or still takes a long afternoon nap.
If I put my toddler to bed later, will they sleep later? Sometimes, and only slowly. Canapari’s advice is to shift it in 10-minute steps and wait a week or two. If your child is already short on sleep, a later bedtime usually just loses hours, so check the morning mood first.
Should bedtime change on weekends? Keep the wake-up time steady and the bedtime follows. A bedtime counted back from a weekday 6:30am wake-up doesn’t fit a Saturday that starts at 8.
Do I need a new bedtime when my child drops a nap? Yes. Daytime sleep is one of the three numbers in the sum, so dropping a nap usually brings bedtime earlier, at least for a while. Run the sum again the week the nap goes.