What time a baby should go to bed

“What time does yours go to bed?”

It is the question parents ask each other, and it is badly framed. Bedtime is not a number you pick off a clock. It is a result.

The calculation

Bedtime is the end of the last nap plus the awake window for their age.

That is all. If your nine-month-old finishes their nap at 3.30 p.m. and their awake window is three and a half hours, they go to bed around 7 p.m. If they finish at 4.30 p.m., they go to bed around 8.

Which is why the time varies from day to day, and why that is normal. Trying to put a child down at 8 p.m. sharp when their nap ended at 2.30 p.m. is asking for five and a half hours of waking from someone who manages three and a half.

Age	After the last nap	Typical bedtime
0 – 3 months	1 – 1 h 45	No fixed time
3 – 6 months	2 – 2 h 30	7 – 8.30 p.m.
6 – 12 months	3 – 4 h	7 – 8.30 p.m.
12 – 18 months	3 h 30 – 5 h	7.30 – 8.30 p.m.
18 months – 3 years	5 – 6 h	7.30 – 8.30 p.m.

Before three months there is no bedtime, because there is no day and night yet. You follow their tiredness signs, full stop.

Total sleep over 24 hOf which at night

Hover over the curve to read an age range.

The window, and what happens when you miss it

There is a moment each evening when your child is tired enough to fall asleep quickly and not yet tired enough to fight it. That window lasts about twenty minutes.

Before it, they do not have enough sleep pressure: they play in their cot for forty minutes.

After it, their body has released cortisol to compensate. They seem wired, laugh too loudly, thrash about — and take longer to fall asleep while waking earlier the next morning. That is the overtired child paradox: they do not fall asleep better, they fall asleep worse.

The signs you are in the window: the stare that fixes, slowing movements, sudden loss of interest in what they were doing. Yawning and eye-rubbing are already a bit late, but still workable. Crying and an arched back mean you missed it.

The mistake everyone makes

Putting them down later so they sleep later.

It sounds logical and it is wrong in the vast majority of cases. A child who falls asleep in sleep debt has more fragmented nights and wakes earlier, not later, because cortisol damages the end of the night — the stretch where deep sleep has already gone.

If mornings are very early in your house, try the opposite: bedtime thirty minutes earlier for a full week. It is the advice that surprises people most and works most often.

Three special cases

The nap that ends too late. After 3.30 – 4 p.m. it mechanically pushes bedtime back. If your evenings are dragging, look at the nap end time before looking anywhere else — it is often the whole explanation.

Time changes and holidays. You move the clock in fifteen-minute steps over several days, and you shift the whole day: waking, meals, naps. Shifting bedtime alone does not work.

The parent who gets home late. That is a real dilemma with no good technical answer. Delaying bedtime to preserve time together has a genuine cost in sleep. A compromise that often works: keep bedtime and move the shared time to the morning — or to a short but daily ritual rather than a long, occasional one.

What matters more than the exact time

Regularity. Bedtime at 8.15 p.m. every evening beats one that swings between 7.30 and 9 depending on the day, even if the average is better.

The biological clock tunes itself to repetition. It is what eventually triggers drowsiness on its own as the time approaches — and that is the moment bedtime stops being a negotiation.