MasterTool

Body Surface Area Calculator

Calculate body surface area (BSA) in m² with both the Mosteller and Du Bois formulas.

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What this tool does

Calculate body surface area (BSA) in m² with both the Mosteller and Du Bois formulas. Both are published estimation formulas; Mosteller is the most commonly used for its simplicity. BSA's clinical applications are for professionals — this tool only computes the area.

How to use the Body Surface Area Calculator

  1. Enter or select body weight in lb.
  2. Enter or select height in in.
  3. Read the calculated result; change any measurement to compare alternatives.

Formula

Mosteller: BSA = √(height cm × weight kg / 3600); Du Bois: BSA = 0.007184 × height(cm)^0.725 × weight(kg)^0.425
weight
Body weight (lb, before metric conversion)
height
Height (in, before metric conversion)

Both are published estimation formulas; Mosteller is the most commonly used for its simplicity. BSA's clinical applications are for professionals — this tool only computes the area.

Worked example

For body surface area calculator, the following measurements illustrate the exact method: Body weight: 154; Height: 69.

Inputs

  • Body weight154 lb
  • Height69 in

Result

  • BSA — Mosteller (m²)1.84
  • BSA — Du Bois (m²)1.85

Results explained

BSA — Mosteller (m²)
BSA — Mosteller (m²) from the formula above. Both are published estimation formulas; Mosteller is the most commonly used for its simplicity. BSA's clinical applications are for professionals — this tool only computes the area.
BSA — Du Bois (m²)
BSA — Du Bois (m²) from the formula above. Both are published estimation formulas; Mosteller is the most commonly used for its simplicity. BSA's clinical applications are for professionals — this tool only computes the area.

Frequently asked questions

BSA is the estimated total surface area of the body in square metres. An average adult is around 1.7–1.9 m².

Mosteller (1987) is simpler and widely used in modern practice; Du Bois (1916) is the historical original. They usually agree within a few percent, and both are shown here.

BSA = √(height in cm × weight in kg ÷ 3600). For 175 cm and 70 kg: √(12250/3600) ≈ 1.85 m².

Clinicians use it to index cardiac output and kidney function and in some dosing contexts. Those uses require professional judgement — this calculator supplies only the number.

The formulas are applied across ages, but paediatric use relies on the same Mosteller formula with the child's own height and weight. Interpretation belongs to the child's clinician.