Body mass index (BMI) adjustments for UK children of South Asian and black African origin allow more accurate assessment of body fat levels.

BMI children 1

What is this?

This is a web calculator which provides adjustments to body mass index in UK children of South Asian and black African origin. Body mass index (BMI), a measure calculated from weight (in kilograms) and height (in metres), is widely used to define whether a child is underweight, normal weight, overweight or very overweight (obese).  

The adjusted values of body mass index (which can be obtained for children aged 4 to 12 years) are intended to provide a more accurate measure of body fatness and weight status than would be obtained from unadjusted body mass index values. You can enter either both the child’s original measured weight and height or the body mass index calculated from weight and height. An adjusted body mass index will be shown, together with the appropriate childhood weight status (underweight, normal weight, overweight, obese) for that body mass index, taking account of the child’s age and sex. These categories are based on comparisons with standard reference populations of UK children (`UK90’) 1.  

Sex :


Age (years) :




Now please insert either a Body Mass Index (BMI in kg/m²) value OR a height (cm) and weight (kg):

BMI (kg/m²) :

Height (cm) :
& Weight (kg):






Why and how has it been developed?

Body mass index (BMI) is a measure which combines weight and height (weight/height2). It, is widely used in children to define weight status (underweight, normal weight, overweight or obese).   However, body mass index can provide misleading information on weight status in UK children of South Asian origin (whose families come from India, Pakistan, Bangladesh or Sri Lanka) and in UK children of black African origin (whose families come from Africa and/or the Caribbean). Evidence suggests that body mass index tends to underestimate body fatness in UK South Asian children and to overestimate it in UK black African children.

For this reason we have used information from studies with very accurate measurements of body fatness in children to calculate adjustments for body mass index in UK children of South Asian and black African origin, so that the adjusted body mass index measures are more closely related to body fatness. These are used in the web calculator on this website to provide a more accurate measure of body fatness and weight status than would usually be obtained.

This research has been undertaken by a research team in the Population Health Research Institute at St George’s, University of London. For further information contact Peter Whincup (email: This email address is being protected from spambots. You need JavaScript enabled to view it.).

More detailed information on the derivation of the BMI adjustments can be found here 


1. Cole TJ, Freeman JV, Preece MA. Body mass index reference curves for the UK, 1990. Arch Dis Child 1995;73(1):25-29.


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Last Updated: Wednesday, 22 March 2017 16:57