© Clinical Marketing Designs, all rights reserved. Calculation by body-weight in the overweight child may result in much higher doses being  administered than necessary; in such cases, the dose should be calculated from an ideal  weight, related to height and age (BNFc). This guidance should therefore be followed for  all pawz.net products; actual body weight should be used unless a child is overweight  when age (equating to ideal body weight) or height should be used when aligning the  wheel.  During the production of pawz.net products, it became obvious that separate wheels for  boys and girls would be impractical. The weights and heights quoted are the mean  (average) based upon the data points at each specific age at the 50th centile. The weights  have been chosen to provide a sensible baselines for dose calculation (e.g. integers) and  therefore some of the ages presented (e.g. 15 and 20 months) may not be as predicted.  • Child Growth Foundation (Charity Reg No 274325). Boys and Girls Growth Charts (Birth-18 years). London: 2 Mayfield Avenue, London. W4 1PW, 1996 (for children aged over 4 years old). • UK-WHO Growth Charts: Early Years (for children aged between 0 and 4 years old).