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Body surface area calculator

Body surface area scales cardiac output, drug clearance and burn assessment better than weight does. Mosteller is the usual clinical choice because it is easy to do in your head.

BSA (Mosteller)
1.8447m2
≈ Rounded Body surface area
BSA (Du Bois)
1.8481 m2
BSA (Haycock)
1.8468 m2
BSA (Gehan-George)
1.8539 m2
BSA (Boyd)
1.8507 m2
Show the working
  1. Weight = 70
  2. Height = 175
  3. BSA (Mosteller) = sqrt(175 * 70 / 3600) = 1.844 66
  4. BSA (Du Bois) = 0.007184 * 175^0.725 * 70^0.425 = 1.848 14
  5. BSA (Haycock) = 0.024265 * 175^0.3964 * 70^0.5378 = 1.846 78
  6. BSA (Gehan-George) = 0.0235 * 175^0.42246 * 70^0.51456 = 1.853 85
  7. BSA (Boyd) = 0.0003207 * 175^0.3 * (70*1000)^(0.7285 - 0.0188*log10(70*1000)) = 1.850 69

Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.

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    The formula

    • Mosteller: BSA = sqrt(height x weight / 3600)
    • Du Bois: BSA = 0.007184 x height^0.725 x weight^0.425
    • Haycock: BSA = 0.024265 x height^0.3964 x weight^0.5378
    • Height in centimetres, weight in kilograms, BSA in square metres.

    Du Bois was fitted in 1916 to nine subjects, one of them a child with dwarfism. Mosteller, from 1987, is simpler and agrees with it closely across normal adults.

    This is a population formula, not a diagnosis. Individual metabolism, body composition and medical history all move the real answer, so treat the number as a starting point and talk to a clinician about anything that matters.

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