All Anthropometry Formulas and values in Paediatrics: Height, Weight, Head circumference

Normal Anthropometric values at birth 

Anthropometry formula for expected parameters in pediatrics

Normal Anthropometric Values at Birth

Parameter	Range	Normal for easy memory
Weight	2.5-3.5kg	3 kg
Length	45-55 cm	50cm
Head circumference	33-37cm	35cm

Calculate body surface area from the weight (kg)

Body Surface area = (4w+7)/(w+90) m²

Ideal weight gain

Age	Expected weight	Rate of weight gain  g/day
Up to 4 months	3-6kg	30g/day
4-8 months	6-8kg	20g/day
8-12 months	8-10 kg	15g/day

Age	Rate of weight gain  g/week
3 months	200 g/week
4 – 6 months	150 g/week
7 – 9 months	100 g/week
10 – 12 months	50 – 75 g/week
1 – 2 years	40 g/week
2 - puberty	30 g/week

All you need to remember for baby weight 

Age	Rate of weight gain
Up to 3 months	30  g/day
3 months to 1 year	400 g/month
3-7 years	2 kg/year
7 years to adolescence	3kg/year

The weight of any baby should multiply in the following rate ideally

Birth Weight (x)	Time	Examples (2.5kg )
2x (Doubles)	5 months	5kg
3x (Triples)	1 year	7.5kg
4x (Four Times)	2 years	10kg
5x (Five times)	3 years	12.5kg
6x (Six times)	5 years	15kg
7x (Seven times)	7 years	17.5kg
10x (Ten times)	10 years	25kg

Formula to calculate expected weight at certain age

Age	Weech Formula
3-12 months	(Age in months + 9) / 2
1-6 years	Age(years)x2 + 8
7-12 years	(Age in years X 7- 5)/2

Inability to gain adequate weight, may be undernutrition. Learn about marasmus and kwashiorkor 

Measurement and calculation of Height

Age	Length at birth
Birth	50cm
3 months	60cm
1 year	75cm
2 years	90cm
4-5 years	100cm
5 years to 10 years	5cm/years
Adolescence	8 cm/year for girls during 12-16 years 10cm/year for boys during 14-18 years

Expected length gain in pediatric

Weech Formula for expected height from 2 years to 12 years

Expected height = age in years x 2 + 77 cm

Rate of gain of length/ height

Age	Gain in length/height
Up to 3 months	3.5cm/month
6-9 months	1.5cm/month
9-12 months	1.3cm/month
2-5 years	6-8cm/year
5 years to 10 years	5cm/years
Adolescence	8 cm/year for girls during 12-16 years 10cm/year for boys during 14-18 years

Head Circumference

Birth	35 cm
3 Months	40 cm
1 years	45 cm
2 years	48cm
5 years	52cm

Rate of growth of Head circumference

Up to  3 months	2 cm/month
3 months – 1 year	2cm/ 3 months
1-3 years	1cm/ 6 month
3-5 year	1cm/ year

Dines formula to estimate HC at 1 years

(HC at birth(cm) + 9.5 ± 2.59)/2 

Learn about abnormality in Head circumference and their causes (Microcephaly, macrocephaly). 

Normal Values of Head circumference and Chest circumference

Chest Circumference 

HC > CC @ Birth by 3cm

HC = CC @ 9-12 months

HC< CC after 1 years

Mid Arm Circumference (MUAC)

Increase in first year       11cm - 16cm

1-5 years                         16cm - 17cm 

Sources: http://www.adsa.org.za/Portals/14/Documents/Clinical20Guideline20Anthropometry.pdf

Essential pediatrics OP Ghai 

Meherban singh Clinical Methods