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Body Surface Area Calculator

Body surface area across the three common formulas. BSA is used for chemotherapy dosing and cardiac index, and the formulas agree within a few percent, which matters when the dose is proportional.

Also called: bsa calculator, body surface area formula.

cm
kg
Formula
Body surface area
1.93

1.93 m² by the Mosteller formula. The other formulas give Du Bois 1.911, Mosteller 1.93, Haycock 1.944 m², a spread of 0.03 m². BSA is used for chemotherapy dosing and cardiac index. The protocol specifies which formula applies.

Du Bois
1.91
Mosteller
1.93
Haycock
1.94
Spread between formulas
0.03
Dose at your rate
0
Formula used
Mosteller
Other formulas
Du Bois 1.911, Mosteller 1.93, Haycock 1.944 m²
On dosing
BSA is used for chemotherapy dosing and cardiac index. The protocol specifies which formula applies.
How this is calculated

For reference only. Verify against your clinical protocol before acting on this number.

Method and background

This is what the calculation gives for the numbers you entered. It is an estimate, not advice, and it knows nothing about your situation beyond those numbers. Rules for United States change on a published schedule; the effective date is shown on every rule-based tool.

How this is calculated

Du Bois from 1916 is the historical standard, Mosteller from 1987 is a simplification that agrees closely and is easy to compute, and Haycock suits children better. The spread between them is typically two to three percent, which is small but not nothing when a cytotoxic dose is calculated directly from it. Which formula a protocol specifies is part of the protocol, not a matter of preference, and substituting one for another changes the dose.

Mosteller, which is simple enough to compute mentally and agrees closely with the older formulas
h
Height in cm
w
Weight in kg

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

a 172 cm 78 kg adult

Height
172 cm
Weight
78 kg
Formula
Mosteller
Dose per square metre, if applicable
0

Body surface area1.93

sqrt(172 x 78 / 3600)

Open this example

the formulas agree closely

Height
172 cm
Weight
78 kg
Formula
Du Bois
Dose per square metre, if applicable
0

Body surface area1.91

boundary: a spread of under 3 percent

Open this example

Method and limits

What it assumes

  • Height and weight measured accurately, since both enter the calculation directly.

What it deliberately does not model

  • BSA-based dosing is itself contested as a method, since it correlates poorly with drug clearance.
  • The formulas were derived on small samples, Du Bois on nine subjects.
  • Extremes of body size fall outside the range the formulas were fitted on.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Which formula should I use?
Whichever the protocol specifies. They differ by two to three percent, which is small unless the dose is calculated directly from it, in which case the protocol governs.