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🏃 Fitness & Health · Rex's Toolbox

Body Surface Area Calculator

BSA by Mosteller, Du Bois, and Haycock formulas.

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Same equations the textbooks use — just way less awkward. Pop in your stats and I'll tell you what the number actually means for you.

Try a scenario

Click to load — tweak from there.

Inputs

Result

BSA — Mosteller (m²)

1.909

BSA — Du Bois (m²)

1.903

BSA — Haycock (m²)

1.917

Cardiac index (L/min/m²)

2.62

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How to use this

  1. 1Enter height (cm).
  2. 2Enter weight (kg).
  3. 3Enter cardiac output (optional) (L/min).
  4. 4Read your bsa — mosteller (m²) on the right — it updates as you type.
  5. 5Hit Share to keep the scenario or send it to someone.

About this calculator

Body surface area drives chemotherapy dosing, cardiac index, and burn assessment. Compare the three most-used formulas side by side from height and weight.

FormulaMosteller: √(height cm × weight kg ÷ 3600).

Worked example

Using the values the calculator loads with:

Inputs

  • Height: 175 cm
  • Weight: 75 kg
  • Cardiac output (optional): 5 L/min

Results

  • BSA — Mosteller (m²): 1.909
  • BSA — Du Bois (m²): 1.903
  • BSA — Haycock (m²): 1.917
  • Cardiac index (L/min/m²): 2.62

What each field means

Inputs

Height (cm)
The height used in the calculation, measured in cm. Starts at 175 cm so you have a working example on load.
Weight (kg)
The weight used in the calculation, measured in kg. Starts at 75 kg so you have a working example on load.
Cardiac output (optional) (L/min)
The cardiac output (optional) used in the calculation, measured in L/min. Starts at 5 L/min so you have a working example on load.

Results

BSA — Mosteller (m²)
Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
BSA — Du Bois (m²)
Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
BSA — Haycock (m²)
Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Cardiac index (L/min/m²)
Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.

FAQ

Which formula should I use?

Mosteller is the most common in oncology because it's simple and agrees closely with Du Bois across normal ranges.

Does BSA hold at extremes?

Less well. In severe obesity the formulas diverge, which is why capped or adjusted dosing exists.

Accuracy and limitations

  • Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.
  • Results do not account for medical conditions, medication, or pregnancy.
  • Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it.

Cite this calculator

Writing about this topic? Grab a citation — every link helps keep these tools free.

APA
RevenueLab. (2026). Body Surface Area (BSA) Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/body-surface-area
HTML
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/body-surface-area" target="_blank" rel="noopener">Body Surface Area (BSA) Calculator — RevenueLab</a> (2026).</p>
Markdown
Source: [Body Surface Area (BSA) Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/body-surface-area) (2026).
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