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The sleep of a 15-month-old

Fifteen months is the heart of the most unstable transition of early childhood: the move from two naps to one.

It does not happen overnight. For several weeks, some days call for two naps and others for one, with no apparent logic. That is normal, and trying to force regularity during this period only adds tiredness.

The rule that served me best: on one-nap days, bring bedtime forward. Thirty to forty-five minutes earlier, without hesitation.

Sleep per 24 h

11 – 14 h

Of which at night

10 – 12 h

Naps

1 – 2

Awake window

3 h 30 – 5 h

One cycle lasts

~ 70 min

Before putting down

~ 12 min

The key point at this age

The reliable signal, and the false ones

The real signal: they refuse one of the two naps consistently for at least two weeks, or the morning nap pushes the afternoon one so far back that bedtime derails. The false signals: three days of refusal, a week of teething, coming back from holiday. You do not make a rhythm decision on the back of one bad week.

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They fall asleep

Their night at 15 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.

    The move to a single nap

    The transition from two naps to one happens between 14 and 18 months for most children. It is the most unstable period of the first year and a half.

    • During the transition, alternate: two naps on some days, one and an earlier bedtime on others.
    • The single nap settles in the early afternoon, between 12.30 and 2 p.m., for 1.5 to 2.5 hours.
    • Resistance at bedtime appears: it is testing the rule, not your patience.
    • Cycles lengthen towards 70 minutes: short naps become rarer.

    The classic trap

    The sign that the move to one nap is ready: they refuse one of the two consistently for two full weeks. Two bad days do not count.

    Falling asleep alone at this age

    ✓ Possible

    Falling asleep alone is the norm at this age. What gets longer is the time spent discussing, demanding and getting back up before sleep wins.

    Put down awake, a child of this age usually takes 10 to 25 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 do you move from 2 naps to 1?

    Gradually, by alternating. On one-nap days, shift it towards 12.30 – 1 p.m. and bring bedtime forward by thirty to forty-five minutes. On two-nap days, keep the old rhythm. The transition usually takes two to six weeks.

    How long should the single nap last?

    One and a half to two and a half hours, in the early afternoon. If it runs past 3.30 p.m. it will push bedtime back: better to wake them gently than to finish the evening at 9.30 p.m.

    My child has been waking at night since the transition — is that connected?

    Yes, very often. The sleep debt during the transition fragments nights. Bringing bedtime forward is the most effective lever, and the most underused.

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