for children shorter than 5 ft, the IBW in kilograms is calculated as ([height in inches]2 × 1.65)/1000. for boys taller than 5 ft, the IBW in kilograms is calculated as 39 + (2.27 × [height in inches − 60]). for girls taller than 5 ft, the IBW in kilograms is calculated as 42 + (2.27 × [height in inches − 60]).