Boyd developed 2 formulas for calculating the body surface area. These are "self-adjusting" equations suitable for all ages.
BSA based on Body Weight
body surface area in square centimeters =
= 4.688 * ((body weight in grams) ^ (X))
body surface area in square meters =
= 0.0004688 * ((body weight in grams) ^ (X))
where:
• X = 0.8168 – (0.0154 * LOG10 (weight in grams))
BSA based on Body Weight and Height
body surface area in square centimeters =
= 3.207 * ((height in cm)^(0.3)) * ((weight in grams)^(Y))
body surface area in square meters =
= (0.0003207) * ((height in cm)^(0.3)) * ((weight in grams)^(Y))
where:
• Y = (0.7285 - (0.0188 * log10 (weight in grams)))
Milazzo modified the equation to use kilograms:
body surface area in square meters =
= (0.00032) * ((height in cm)^(0.3)) * ((1000 * (weight in kilograms))^(A))
where:
• A = (0.7285 - (0.0188 * (3 + LOG10(weight in kilograms))))
