# Body Surface Area Calculator

> Calculate body surface area in square metres from height and weight with the Mosteller, DuBois, Haycock and Gehan–George formulas side by side.

Category: Health & fitness · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/body-surface-area-calculator

Body surface area (BSA) is estimated from height and weight. Several published formulas exist; they usually agree within a few per cent for adults. This supports, and does not replace, clinical judgement.

Also called: BSA calculator.

## Inputs
- Units (options: Metric (cm, kg), US (ft, in, lb); default metric)
- Height (unit cm; default 170)
- Height (feet) (unit ft; default 5)
- Height (inches) (unit in; default 9; optional)
- Weight (unit kg; default 70)
- Weight (unit lb; default 154)

## Results
- BSA (Mosteller)
- BSA (DuBois & DuBois)
- BSA (Haycock)
- BSA (Gehan & George)

## Formula

```
Mosteller: √(H × W ÷ 3600);  DuBois: 0.007184 × W^0.425 × H^0.725;  Haycock: 0.024265 × W^0.5378 × H^0.3964;  Gehan–George: 0.0235 × W^0.51456 × H^0.42246
```

Where:
- H: height in cm (1 in = 2.54 cm)
- W: weight in kg (1 lb = 0.45359237 kg)

## Worked example
1. Mosteller: √(180 × 80 ÷ 3600) = √4 = 2.00 m².
2. DuBois: 0.007184 × 80^0.425 × 180^0.725 = 0.007184 × 6.43 × 43.2 ≈ 2.00 m².

**Result:** A person 180 cm tall weighing 80 kg has a body surface area of about 2.0 m² by both Mosteller and DuBois.

## What the result means

Typical adult values are roughly 1.6–2.0 m². BSA is used to index measurements such as cardiac output (cardiac index) and kidney function, and in some dosing protocols, where the prescriber chooses the formula.

## Assumptions and limits
- Height and weight are measured, not estimated.
- Formulas were derived largely in adults (Haycock includes infants and children).
- Formulas diverge at extremes of body size, particularly severe obesity and very small children.
- Not a dosing tool: medicine doses must come from the prescriber, the product label or local protocol.

## Questions

### Which formula is best?

Mosteller is simple and widely used; DuBois is the oldest and still common in physiology. For most adults the difference is a few hundredths of a square metre. Follow the formula your protocol specifies.

### Why is GFR reported per 1.73 m²?

1.73 m² was the average adult BSA when the convention was set, so indexing to it lets kidney function be compared between people of different sizes.

## Related calculators
- [GFR Calculator](https://calculators.geekmidst.com/calculators/gfr-calculator)
- [BMI Calculator](https://calculators.geekmidst.com/calculators/bmi-calculator)
- [Body Type Calculator](https://calculators.geekmidst.com/calculators/body-type-calculator)

_This is a general screening estimate for adults, not medical advice or a diagnosis. Talk to a qualified health professional about your health._

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/body-surface-area-calculator