Date of birth is needed to accurately work out the BMI of anyone under 18 years old.
For example, 15 11 2018
Sex is needed to work out the BMI of anyone under 18 years old. This is because there are different growth charts for females and males.
Select the child's sex at birth. Speak to a GP if you need more advice about this.
A child's BMI can change depending on when they were measured.