Is my baby overweight if they're at the 95th percentile?

Not necessarily. For babies under 2, higher percentiles are generally not a concern as long as weight and length are proportional and the baby is following their curve. The concept of childhood overweight/obesity applies more after age 2. Discuss with your pediatrician if you're concerned.

Should I put my baby on a diet if they're gaining too fast?

Never restrict an infant's food intake without medical advice. Babies need adequate nutrition for brain development and growth. If you're concerned about rapid weight gain, talk to your pediatrician — they'll consider the full picture including length, feeding method, and family history.

Do breastfed and formula-fed babies grow differently?

Yes. Breastfed babies tend to gain weight faster in the first 3–4 months, then slower after that compared to formula-fed babies. By 12 months, weights tend to converge. The WHO charts were built from breastfed baby data, so breastfed babies may track slightly differently on CDC charts.

How accurate are home baby scales?

Dedicated infant scales are accurate to within 0.5 oz (15 g). For consistency, weigh your baby at the same time of day, with the same amount of clothing (ideally just a diaper), on the same scale. Don't compare readings from different scales.

My premature baby is small for their age. Is that normal?

Yes. Premature babies are typically plotted using corrected age (chronological age minus weeks of prematurity) for the first 2–3 years. A 4-month-old born 2 months early would be plotted at 2 months on the growth chart. Most premature babies catch up by age 2–3.

Average Baby Weight by Month: What to Expect in Year One

"How much should my baby weigh?" is one of the most searched questions by new parents. The WHO provides detailed weight-for-age data for boys and girls from birth through the first year. Here's what to expect — and what actually matters.

What Is the Average Birth Weight?

Most full-term babies are born weighing between 5.5 and 10 pounds (2.5–4.5 kg). The WHO median birth weight differs slightly between boys and girls.

According to WHO Child Growth Standards, the median birth weight is 3.3 kg (7.3 lb) for boys and 3.2 kg (7.1 lb) for girls.

Source: WHO (2006)

It's normal for newborns to lose 5–10% of their birth weight in the first few days due to fluid loss. Most babies regain their birth weight by 10–14 days of age.

What Is the Average Baby Weight by Month?

Here are the WHO 50th percentile (median) weights for boys and girls during the first year:

Age	Boys (50th percentile)	Girls (50th percentile)
Birth	7.3 lb (3.3 kg)	7.1 lb (3.2 kg)
1 month	9.7 lb (4.4 kg)	9.0 lb (4.1 kg)
2 months	11.5 lb (5.2 kg)	10.6 lb (4.8 kg)
3 months	13.2 lb (6.0 kg)	12.1 lb (5.5 kg)
4 months	14.6 lb (6.6 kg)	13.4 lb (6.1 kg)
5 months	15.9 lb (7.2 kg)	14.6 lb (6.6 kg)
6 months	17.0 lb (7.7 kg)	15.7 lb (7.1 kg)
7 months	17.9 lb (8.1 kg)	16.6 lb (7.5 kg)
8 months	18.8 lb (8.5 kg)	17.4 lb (7.9 kg)
9 months	19.6 lb (8.9 kg)	18.1 lb (8.2 kg)
10 months	20.3 lb (9.2 kg)	18.7 lb (8.5 kg)
11 months	20.9 lb (9.5 kg)	19.4 lb (8.8 kg)
12 months	21.4 lb (9.7 kg)	19.8 lb (9.0 kg)

Healthy infants typically double their birth weight by 4–5 months and triple it by 12 months of age, according to WHO growth standards.

Source: WHO (2006)

Remember: these are medians (50th percentile). Half of healthy babies weigh less and half weigh more. Your baby's percentile matters less than whether they follow their own curve consistently.

How Fast Should My Baby Gain Weight?

Weight gain varies by age. The general pattern is rapid early growth that gradually slows:

Age Range	Expected Weight Gain
0–3 months	5–7 oz (150–200 g) per week
3–6 months	4–5 oz (110–140 g) per week
6–12 months	2–4 oz (55–110 g) per week

Growth spurts can temporarily increase these rates. Common growth spurt periods include 2 weeks, 6 weeks, 3 months, and 6 months.

What If My Baby Is Smaller or Larger Than Average?

Being above or below the 50th percentile is completely normal. What matters is the pattern over time, not any single measurement.

Don't worry if:

Your baby has always been at the 15th or 85th percentile — they're following their curve
There's a small fluctuation between visits — daily hydration and feeding affect weight
Your baby is smaller but meeting all developmental milestones

Talk to your pediatrician if:

Your baby crosses two or more percentile lines in either direction
Weight falls below the 3rd percentile or above the 97th
There's a sudden plateau in weight gain lasting more than 2–3 weeks
Your baby is not regaining birth weight by 2 weeks of age

The AAP recommends that babies who haven't regained their birth weight by 2 weeks of age be evaluated for feeding difficulties, with assessment of intake, output, and weight gain.

Source: AAP (2024)

Do Boys and Girls Grow Differently?

Yes. Boys tend to be slightly heavier and longer than girls at every age during the first year. This is why the WHO publishes separate growth curves for each sex.

The differences are small — typically 0.5–1.5 lb (0.2–0.7 kg) at any given month — but using the wrong chart can put your baby at an inaccurate percentile.

How Can I Track My Baby's Weight at Home?

You don't need to weigh your baby daily — weekly or biweekly is enough between pediatric visits. Babylitics makes it easy to see the big picture:

Log weight measurements in pounds or kilograms
See your baby's weight plotted on WHO growth curves with percentile bands
Track growth velocity — how fast your baby is gaining over time
Compare boys' and girls' data against the correct gender-specific WHO charts
Share growth charts with your pediatrician via a secure link or QR code

One measurement is a data point. A series of measurements on a growth curve tells a story — and that story is what your pediatrician cares about.

Frequently Asked Questions

Track your baby's weight and see it on WHO growth curves — free for 15 days, no credit card required.

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