Baby Growth Chart: Weight, Height, and Percentiles Explained

What Is a Growth Curve?

A growth curve is a chart that compares your baby's weight, height, and head circumference with thousands of other babies of the same age and sex.

Pediatricians use the WHO (World Health Organization) growth charts as a reference. These are based on data from healthy breastfed babies across different countries.

What Are Percentiles?

A percentile indicates your baby's position relative to other babies.

• 50th percentile: the baby is at the average. Half of babies weigh more, half weigh less
• 25th percentile: 25% of babies weigh less than yours
• 75th percentile: 75% of babies weigh less than yours
• 3rd percentile: only 3% of babies weigh less
• 97th percentile: only 3% of babies weigh more

What Really Matters

A single percentile reading doesn't tell you much. What matters is:

1. The trajectory: the baby following their own curve over the months
2. Crossing curves: rising or dropping significantly from their usual percentile
3. Proportionality: weight and height being proportional to each other

A baby at the 15th percentile who has always been at the 15th percentile is just as healthy as one at the 85th.

Average Baby Weight Month by Month

Boys

| Age | P3 | P50 (average) | P97 | |-----|-----|---------------|------| | Birth | 5.5 lb (2.5 kg) | 7.3 lb (3.3 kg) | 9.5 lb (4.3 kg) | | 1 month | 7.1 lb (3.2 kg) | 9.5 lb (4.3 kg) | 12.6 lb (5.7 kg) | | 2 months | 8.8 lb (4.0 kg) | 11.5 lb (5.2 kg) | 15.0 lb (6.8 kg) | | 3 months | 10.4 lb (4.7 kg) | 13.2 lb (6.0 kg) | 17.0 lb (7.7 kg) | | 4 months | 11.5 lb (5.2 kg) | 14.8 lb (6.7 kg) | 18.5 lb (8.4 kg) | | 6 months | 13.4 lb (6.1 kg) | 17.2 lb (7.8 kg) | 21.4 lb (9.7 kg) | | 9 months | 15.4 lb (7.0 kg) | 19.6 lb (8.9 kg) | 24.0 lb (10.9 kg) | | 12 months | 16.5 lb (7.5 kg) | 21.2 lb (9.6 kg) | 26.0 lb (11.8 kg) |

Girls

| Age | P3 | P50 (average) | P97 | |-----|-----|---------------|------| | Birth | 5.3 lb (2.4 kg) | 7.1 lb (3.2 kg) | 9.3 lb (4.2 kg) | | 1 month | 6.6 lb (3.0 kg) | 8.8 lb (4.0 kg) | 11.7 lb (5.3 kg) | | 2 months | 8.2 lb (3.7 kg) | 10.8 lb (4.9 kg) | 14.1 lb (6.4 kg) | | 3 months | 9.5 lb (4.3 kg) | 12.3 lb (5.6 kg) | 15.9 lb (7.2 kg) | | 4 months | 10.6 lb (4.8 kg) | 13.7 lb (6.2 kg) | 17.4 lb (7.9 kg) | | 6 months | 12.3 lb (5.6 kg) | 15.9 lb (7.2 kg) | 20.3 lb (9.2 kg) | | 9 months | 14.1 lb (6.4 kg) | 18.1 lb (8.2 kg) | 22.9 lb (10.4 kg) | | 12 months | 15.2 lb (6.9 kg) | 19.6 lb (8.9 kg) | 24.7 lb (11.2 kg) |

Average Baby Height Month by Month

Boys

| Age | P3 | P50 (average) | P97 | |-----|-----|---------------|------| | Birth | 18.1 in (46 cm) | 19.7 in (50 cm) | 21.3 in (54 cm) | | 3 months | 22.4 in (57 cm) | 24.0 in (61 cm) | 26.0 in (66 cm) | | 6 months | 24.8 in (63 cm) | 26.4 in (67 cm) | 28.3 in (72 cm) | | 9 months | 26.4 in (67 cm) | 28.3 in (72 cm) | 29.9 in (76 cm) | | 12 months | 28.0 in (71 cm) | 29.9 in (76 cm) | 31.5 in (80 cm) |

Girls

| Age | P3 | P50 (average) | P97 | |-----|-----|---------------|------| | Birth | 17.7 in (45 cm) | 19.3 in (49 cm) | 20.9 in (53 cm) | | 3 months | 22.0 in (56 cm) | 23.6 in (60 cm) | 25.2 in (64 cm) | | 6 months | 24.0 in (61 cm) | 26.0 in (66 cm) | 27.6 in (70 cm) | | 9 months | 25.6 in (65 cm) | 27.6 in (70 cm) | 29.5 in (75 cm) | | 12 months | 27.2 in (69 cm) | 29.1 in (74 cm) | 31.1 in (79 cm) |

Head Circumference

Head circumference is monitored to assess brain growth.

| Age | Average (boys) | Average (girls) | |-----|---------------|-----------------| | Birth | 13.8 in (35 cm) | 13.4 in (34 cm) | | 3 months | 15.7 in (40 cm) | 15.4 in (39 cm) | | 6 months | 16.9 in (43 cm) | 16.5 in (42 cm) | | 12 months | 18.1 in (46 cm) | 17.7 in (45 cm) |

When to Be Concerned

Weight Warning Signs

• Weight loss after the first 10 days of life
• Baby has not regained birth weight by 2 weeks
• Downward crossing of 2 or more percentile bands
• Weight gain less than 1 lb (500g) per month in the first 4 months
• Consistently gaining weight well above expected

Height Warning Signs

• Height persistently below the 3rd percentile
• Growth stalled for more than 2 consecutive check-ups
• Large discrepancy between weight percentile and height percentile

Head Circumference Warning Signs

• Very rapid growth (may indicate hydrocephalus)
• Very slow growth (may indicate microcephaly)
• Persistently bulging fontanelle (soft spot)

Factors That Influence Growth

• Genetics: tall parents tend to have tall children
• Nutrition: exclusive breastfeeding until 6 months is ideal
• Health: chronic illnesses or frequent infections can affect growth
• Prematurity: premature babies use corrected age until 2 years
• Hormones: thyroid problems or growth hormone deficiency can have an impact

Tips for Tracking Growth

• Take your baby to all well-baby check-ups
• Always use the same scale and measuring tape when measuring at home
• Record the data to track progress over time
• Don't compare with other babies. Each one follows their own curve
• Trust the pediatrician to interpret the numbers

Well-Baby Visit Frequency

| Period | Frequency | |--------|-----------| | 0-6 months | Monthly | | 6-12 months | Every 2 months | | 12-24 months | Every 3 months | | 2-5 years | Every 6 months |

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The numbers are references, not goals. What matters most is that your baby is growing consistently, eating well, and reaching developmental milestones. Your pediatrician is your best ally in this journey.