At every check-up, your baby is weighed and measured, and you may hear a percentile that leaves you wondering whether it is good or bad. Comparing with other babies can add to the worry. Understanding baby growth charts helps you see what really matters: a steady pattern over time, not a single number.
Quick answer: tracking baby growth
- Three measurements: weight, length and head circumference.
- Percentiles compare your baby with others of the same age and sex; the 50th is average, not a target.
- The trend matters most: steady growth along a curve is a good sign.
- Newborns lose weight in the first days and usually regain birth weight by 2 weeks.
How growth is measured
- Weight: on baby scales, without clothes or nappy.
- Length: lying flat until about 2 years.
- Head circumference: a tape around the widest part of the head, reflecting brain growth.
Understanding percentiles
If your baby is on the 25th percentile for weight, 25 out of 100 babies of the same age weigh less and 75 weigh more. Babies on the 5th or 95th percentile can be perfectly healthy. Doctors look at whether your baby follows a similar line over time and whether weight, length and head size are in proportion.
Typical growth in the first year
- most babies double their birth weight by around 4 to 6 months and triple it by 12 months
- length increases by about 25 cm in the first year
- growth spurts often bring extra hunger and fussiness for a few days
- breastfed and formula-fed babies may grow slightly differently; WHO charts are based on breastfed babies
Supporting healthy growth
- feed responsively. See the baby feeding schedule
- start nutritious solids around 6 months. See nutrient-rich foods for babies
- keep regular check-ups
- use corrected age for premature babies
When to talk to your doctor
- your baby has not regained birth weight by 2 weeks
- weight drops across two or more percentile lines
- poor feeding, fewer wet nappies or low energy
- head size growing much faster or slower than expected
- you are worried about your baby’s size
Frequently asked questions
Is a small baby a problem?
Not if they grow steadily and are developing well. Size is often inherited from parents.
How often should my baby be weighed?
Follow your health service’s schedule. Weighing too often can cause worry over normal day-to-day changes.
Do growth spurts affect sleep?
Yes, babies may feed and wake more for a few days during growth spurts.
Sources
- World Health Organization: Child growth standards
- CDC: Growth charts
- NHS: Your baby’s weight and height
This guide is general information, not medical advice. If you are worried about your baby’s growth, talk to your doctor or health visitor.