What is the average birth weight in kg?

The average birth weight for a full-term baby is approximately 3.3–3.5 kg (7 lbs 4 oz to 7 lbs 11 oz). A healthy birth weight range is generally considered 2.5 kg to 4.5 kg (5 lbs 8 oz to 9 lbs 15 oz). Babies below 2.5 kg are considered low birth weight.

How do I convert baby weight from kg to lbs?

Multiply kilograms by 2.2046 to get pounds. For example: 3.5 kg × 2.2046 = 7.716 lbs, which is 7 lbs 11.5 oz. To convert to pounds and ounces: take the decimal part of the pounds value and multiply by 16 to get ounces. So 7.716 lbs = 7 lbs and (0.716 × 16) = 11.5 oz.

What is the 50th percentile weight at 6 months?

According to WHO growth standards, the 50th percentile (median) weight at 6 months is approximately 7.9 kg (17.4 lbs) for boys and 7.3 kg (16.1 lbs) for girls. Percentiles describe where a baby falls compared to other babies of the same age — the 50th percentile means exactly average.

Baby Growth Chart Guide: Weight and Height Conversions (kg, lbs, cm, inches)

US vs. WHO Growth Charts

Two major growth chart systems are used worldwide. The CDC growth charts (used in the United States) are based on data from American children and express measurements in pounds and inches. The WHO Multicentre Growth Reference Study charts were developed from children raised in optimal conditions across six countries and use kilograms and centimeters as primary units. Most US pediatricians use WHO charts for children under age 2 and CDC charts for ages 2 and above.

Understanding both systems — and knowing how to convert between them — helps you follow your baby's progress at international clinics, in parenting apps that use metric, or when reading research studies.

Birth Weight Conversion Reference

Weight (kg)	Weight (lbs & oz)	Classification
2.5 kg	5 lbs 8 oz	Low birth weight threshold
2.7 kg	5 lbs 15 oz	Small but healthy
3.0 kg	6 lbs 10 oz	Average range
3.3 kg	7 lbs 4 oz	Average (WHO median)
3.5 kg	7 lbs 11 oz	Average range
3.8 kg	8 lbs 6 oz	Larger average
4.0 kg	8 lbs 13 oz	Large but normal
4.5 kg	9 lbs 15 oz	High birth weight threshold

To convert kg to lbs: multiply by 2.2046. To convert lbs to kg: multiply by 0.4536. Use our weight converter for quick calculations.

Monthly Length Milestones: Birth to 12 Months

The values below are 50th percentile (median) figures from WHO growth standards, averaged across boys and girls. Individual babies vary considerably — a healthy range spans roughly the 5th to 95th percentile.

Age	Length (cm)	Length (inches)	Weight (kg) — 50th %ile	Weight (lbs)
Birth	49.9 cm	19.6 in	3.3 kg	7.3 lbs
1 month	54.7 cm	21.5 in	4.5 kg	9.9 lbs
2 months	58.4 cm	23.0 in	5.6 kg	12.3 lbs
3 months	61.4 cm	24.2 in	6.4 kg	14.1 lbs
4 months	63.9 cm	25.2 in	7.0 kg	15.4 lbs
5 months	65.9 cm	25.9 in	7.5 kg	16.5 lbs
6 months	67.6 cm	26.6 in	7.9 kg	17.4 lbs
7 months	69.2 cm	27.2 in	8.3 kg	18.3 lbs
8 months	70.6 cm	27.8 in	8.6 kg	19.0 lbs
9 months	72.0 cm	28.3 in	8.9 kg	19.6 lbs
10 months	73.3 cm	28.9 in	9.2 kg	20.3 lbs
11 months	74.5 cm	29.3 in	9.4 kg	20.7 lbs
12 months	75.7 cm	29.8 in	9.6 kg	21.2 lbs

How to Convert Baby Measurements

Kilograms to Pounds and Ounces

Multiply kg by 2.2046 to get decimal pounds (e.g., 7.9 kg × 2.2046 = 17.42 lbs).
Take the decimal part (0.42) and multiply by 16 to get ounces (0.42 × 16 = 6.7 oz).
Result: 17 lbs 6.7 oz.

Centimeters to Inches

Divide cm by 2.54 to get inches (e.g., 67.6 cm ÷ 2.54 = 26.6 inches).
Alternatively, multiply cm by 0.3937.

Use our length converter to convert centimeters to inches instantly, or the weight converter for kg-to-lbs calculations.