Baby Sleep Schedule Calculator

What a wake window is

A wake window is the length of time a baby can comfortably stay awake between sleeps before becoming overtired. They are short in the newborn period and lengthen steadily through the first two years.

Using wake windows rather than a clock-based schedule tends to work better for younger babies, because their sleep needs change quickly and unevenly. The window tells you roughly when to start settling, which is usually a little before your baby seems obviously tired.

Typical wake windows and sleep needs by age

• 0–6 weeks: 45–60 minutes awake · 14–17 hours total sleep · naps are irregular
• 2–3 months: 1–1.75 hours · 14–16 hours · 4–5 naps
• 4–5 months: 1.75–2.5 hours · 12–16 hours · 3–4 naps
• 6–8 months: 2.25–3 hours · 12–15 hours · 2–3 naps
• 9–12 months: 3–4 hours · 12–15 hours · 2 naps
• 12–18 months: 3.5–5 hours · 11–14 hours · 1–2 naps
• 18–36 months: 5–6 hours · 11–14 hours · 1 nap

These are broad ranges, and there is genuine variation within them. Some babies consistently need more sleep than average and some noticeably less.

Reading tired cues

Cues are more reliable than the clock, though they are easy to miss until you know what you are looking for.

Early cues: staring into the distance, reduced engagement, becoming quieter, rubbing eyes or ears, pulling at hair.

Later cues: yawning, fussiness, arching away, clinginess.

Overtired: crying that is hard to settle, a burst of frantic activity, back-arching, difficulty falling asleep despite obvious exhaustion.

Overtiredness is counterintuitive: it makes falling asleep harder, not easier, because cortisol rises when a baby is kept awake past their window. Catching the early cues generally makes settling considerably easier.

Sleep regressions and why they happen

Periods of disrupted sleep around 4, 8 to 10, and 18 months are commonly described as regressions. The term is slightly misleading — what is usually happening is developmental progress rather than a step backwards.

The change around four months is the most significant, because sleep architecture matures permanently. Babies begin cycling between sleep stages more like adults, which means more brief wakings between cycles. This is a lasting developmental change, not a phase that reverses.

Later disruptions often coincide with rolling, crawling, standing, separation awareness, or language bursts. They typically settle within a few weeks once the new skill is consolidated.

Safe sleep, which matters more than any schedule

For every sleep, day and night, current guidance is consistent:

• Always place your baby on their back, until they can roll both ways independently
• Use a firm, flat sleep surface with a fitted sheet and nothing else in the space
• No pillows, duvets, bumpers, positioners, or soft toys
• Room-share for at least the first six months, without bed-sharing
• Keep the room at a comfortable temperature and avoid overheating
• Keep the sleep space smoke-free

If you are considering bed-sharing, discuss safer approaches with your health visitor rather than doing it unplanned when exhausted.

A realistic word about all of this

Schedules are a guide, not a standard to be met. Plenty of babies do not follow them, and that reflects normal variation rather than anything you have done.

Night waking in the first year is normal and expected, including in babies who previously slept longer stretches. If sleep deprivation is affecting your mental health, please tell your health visitor or GP — that is a genuine and common reason to ask for support, not a complaint you need to justify.

Common Questions