Baby sleep milestones Practical, science-based guidance — no fluff.
6–8 weeks
Longest stretch lengthens to 4–6 hours at night. First social smiles. Circadian rhythm begins to organize.
3–4 months
Mature 4-stage sleep cycles develop. Some babies sleep 6–8 hours. The 4-month regression often hits here.
6 months
Most babies are physiologically capable of sleeping 10–12 hours with adequate daytime calories. Good window for sleep training.
9 months
Drop from 3 → 2 naps. Separation anxiety peaks and may briefly disrupt sleep.
12–18 months
Transition from 2 → 1 nap. Bedtime may need to shift later temporarily.
2 years
11–14 hours total, single afternoon nap, predictable bedtime. Imagination develops — first dream/nightmare reports.
⚠️ Every baby is different. Follow sleepy cues. Not medical advice. Consult your pediatrician.
Related
Medical disclaimer. Everything on this page is general educational information and is not a substitute for professional medical advice. Sleep needs vary from person to person. If you have ongoing sleep problems, talk to a licensed healthcare professional.