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The sleep of an 18-month-old

At eighteen months the rhythm is finally simple: one nap after lunch, one long night. On paper it is the most comfortable period since birth.

In practice, the difficulties that remain are almost all behavioural. It is no longer about physiology but about limits: the glass of water, one more story, getting out of bed for the third time.

It is also the age when night terrors appear, which alarm parents a great deal and get confused with nightmares. They are not the same thing and they are not handled the same way.

Sleep per 24 h

11 – 14 h

Of which at night

10 – 12 h

Naps

1

Awake window

5 h – 6 h

One cycle lasts

~ 75 min

Before putting down

~ 10 min

The key point at this age

Night terror or nightmare?

A night terror happens in deep sleep, so at the start of the night, within two to three hours of bedtime. The child screams, thrashes, has their eyes open — and does not recognise you, because they are asleep. You do not wake them: you make the surroundings safe and you wait. The next day they remember nothing. A nightmare, by contrast, comes at the end of the night in REM sleep: the child is awake, recognises you, can be comforted and can tell you about it in the morning.

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They fall asleep

Their night at 18 months, minute by minute

    The whole night, at a glance

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    The timer: when can I put them down?

    Start it the second they fall asleep in your arms.

    --:--before putting them down

    While you wait, keep them against you and try not to move. The countdown will tell you when their sleep is deep enough for the transfer.

    Keep this tab open. The timer stays accurate even if the screen turns off.

    One nap, and a lot of character

    The rhythm is simple and stable: one nap after lunch, one long night. The difficulties that remain are almost all behavioural, not physiological.

    • The bedtime routine becomes your main tool: short, identical, predictable.
    • Night terrors occur in deep sleep, at the start of the night. The child remembers nothing: you do not wake them.
    • Nightmares, by contrast, come at the end of the night in REM sleep, and get told in the morning.
    • Moving to a big bed is not needed before two, and rarely helps sleep.

    The classic trap

    A nap that runs past 3.30 p.m. pushes bedtime back. If your evenings are dragging, look at the end of the nap first.

    Falling asleep alone at this age

    ✓ Possible

    They fall asleep alone, but test the rule. A short, rigorously identical routine shortens falling asleep more than any negotiation.

    Put down awake, a child of this age usually takes 10 to 30 minutes to fall asleep. That squirming is normal.

    How much sleep they need, age by age

    The shaded band is the normal range over 24 hours. Hover to read an age range.

    0h4h8h12h16hbirth6 mo1 year18 mo2 years30 mo3 years
    Total sleep over 24 hOf which at night

    Hover over the curve to read an age range.

    The questions of this age

    How much should an eighteen-month-old sleep?

    Between 11 and 14 hours out of 24, of which 10 to 12 at night plus a nap of one and a half to three hours.

    My eighteen-month-old refuses to go to bed — what do I do?

    A short, identical, non-negotiable routine, and exactly one thing you are willing to repeat every evening — a glass of water, for instance, served before bed and not after. Resistance tests the stability of the rule: the more the rule moves, the more they will test it.

    Should the nap be dropped at 18 months?

    No. The nap remains necessary until around three to five years. If it prevents falling asleep in the evening, shorten it or move it earlier rather than dropping it.

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