Baby Sleep Calculator

Newborns (0–3 months) need 14–17 hours of total sleep per 24 hours, spread across multiple sleep periods of 2–4 hours. They have not yet developed a circadian rhythm — it emerges around 3–4 months as melatonin production begins to synchronise with light/dark cycles.

Most babies begin to consolidate night sleep into a 5–6 hour stretch between 3–6 months, though this varies widely. 'Sleeping through the night' in infant sleep science typically means a 5-hour stretch, not 8 hours. Many babies continue waking 1–2 times per night through 12 months — this is developmentally normal.

A wake window is the amount of time a baby can comfortably stay awake between sleep periods before becoming overtired. Wake windows start at just 45–60 minutes for newborns and gradually increase to 3–4 hours for toddlers. Respecting wake windows is the most important principle in infant sleep scheduling.

Signs of overtiredness include: rubbing eyes, pulling ears, glazed stare, fussiness that escalates despite comfort, arching back, reduced interest in surroundings, and yawning. Paradoxically, overtired babies often seem wired rather than sleepy — cortisol released when overly tired produces a state of hyperarousal.

Yes — darkness is one of the best sleep environment conditions for babies from birth. It stimulates melatonin production and reinforces day/night differentiation. A fully dark room during naps and night sleep is recommended. Brief exposure to bright morning light after wake helps set the circadian clock.

The American Academy of Pediatrics (AAP) recommends all babies be placed on their backs (supine) to sleep on a firm, flat surface for every sleep until age 1. This position is associated with the lowest SIDS risk. Once a baby can roll both ways independently, repositioning during sleep is not necessary.