Can you tell me exactly how much of sleep does my newborn actually need?

From newborns to one month old, about 16–20 hours in every 24 (say 6–8 sleeps of 2–3 hours) — then by 3–4 weeks old (to due date), one 5–6-hour sleep at night (e.g. 10 pm–4 am). As a newborn, active REM sleep is the most dominant part of a wee baby’s sleep pattern (say 50 per cent). By the time a baby is just 3–4 months old their sleep style is maturing, and so the quieter quiescence (non-REM) sleep becomes more dominant (with its deep even breathing, lying still, and occasional startle jerk).