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Sunny Seed

Your baby at 3 months

Everything that lines up at this one age — growth figures from the WHO standard, sleep norms, the milestones whose normal window covers this month, and the vaccine doses due. Percentiles are called centiles in the UK; the numbers are identical.

Growth at 3 months

Median means half of babies are above and half below. Being away from the median is not a problem in itself — following your own curve is what matters.

Median (50th) · BoysMiddle half (25th–75th) · BoysMedian (50th) · GirlsMiddle half (25th–75th) · Girls
Weight6.37 kg5.88–6.89 kg5.84 kg5.36–6.36 kg
Length61.4 cm60.0–62.8 cm59.8 cm58.4–61.2 cm
Head circumference40.5 cm39.7–41.3 cm39.5 cm38.7–40.4 cm

Want the number for your own baby? Open the percentile calculator

Sleep at 3 months

Ranges, not targets. Healthy babies sit outside them regularly.

Total per day
14 h17 h
One nap
30 m2 h
Night sleep
8 h9 h

Milestones in this window

The window is when a skill usually appears — not a deadline. Appearing later than the window is a reason to mention it at a check-up, not to worry alone.

Vaccine doses at this age

Routine doses only, from the national schedules as published by each country's health authority. Vaccinations always follow chronological age, even for premature babies.

United Kingdom

  • DTaPdose 2
  • Hepatitis Bdose 2
  • Hibdose 2
  • Polio (IPV)dose 2
  • Meningococcal Bdose 2
  • Rotavirusdose 2

Reference figures, not medical advice. Every baby differs; a check-up answers questions a table cannot.