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Enter your values, then click Calculate result.How this calculator helps
Estimate body surface area in square metres using the Mosteller formula from height in centimetres and body weight in kilograms. Body surface area, abbreviated BSA, is an estimated total skin surface expressed in square metres. This page uses the Mosteller equation only. It takes measured height and weight, multiplies them, divides by 3,600 and takes the square root. The result is a mathematical estimate rather than a direct surface measurement. Other published equations can produce different values, so identify the formula whenever comparing this result with a clinical record.
How to use it
- 1
Choose the stated method or shape and read the labels before replacing the example values.
- 2
Enter the measurements in the exact units shown. Use the inputs described in the methodology below.
- 3
Click Calculate result. Editing inputs keeps the previous submitted result visible until you calculate again.
- 4
Compare the supporting figures with the formula and worked example, then review the method’s specific limitations.
Formula and methodology
BSA in m² = √(height in cm × weight in kg ÷ 3,600).
The calculator applies the displayed arithmetic to the values entered on this device. It does not silently load a local tax rate, currency conversion or commercial assumption.
Worked calculation example
At 170 cm and 70 kg, Mosteller BSA is approximately 1.818 m². The output is area, not a medication dose.
How to interpret your result
This method applies only within the stated scope. Mosteller estimate only, without validation for individual clinical use. Does not diagnose, assess health or calculate medication doses. The worked scenarios below identify the measurements and conventions needed to interpret the displayed output.
For different inputs or formulas, use Height Calculator; Body Fat Calculator; Corrected Calcium Calculator.
Related questions this calculator covers
- body surface area calculator
- bsa calculator
- body area surface calculator
- surface area body calculator
Scenario comparison
| Scenario | What it shows |
|---|---|
| 170 cm and 70 kg | approximately 1.818 m² using Mosteller. |
| 180 cm and 80 kg | exactly 2 m² before display rounding. |
| Unconverted pounds | incompatible with the kg input; convert first. |
Common mistakes to avoid
- Entering metres in the centimetre field.
- Confusing estimated BSA with BMI.
- Turning the area into an unverified medication dose.
Reproduce the equation shown on this page using the same entered values. At 170 cm and 70 kg, Mosteller BSA is approximately 1.818 m². The output is area, not a medication dose. Keep input units and the selected method with any recorded result. Check unusual measurements rather than relying on extra displayed decimal places.
Authoritative reference. Mosteller estimate only, without validation for individual clinical use. Does not diagnose, assess health or calculate medication doses.What can affect the result?
Preparing height and weight
Height must be centimetres and weight must be kilograms. Convert inches by multiplying by 2.54, and convert pounds by multiplying by 0.45359237. A height written as 5 feet 7 inches must first become 67 inches; entering 5.7 as if it were centimetres would be a serious unit error. Use current measurements from the same visit when possible. Clothing, scale error and an estimated rather than measured height can affect the output.
BSA and BMI answer different questions
BSA estimates an area. BMI divides weight in kilograms by height in metres squared and is reported in kg/m². Although both calculations use height and weight, their equations and meanings differ. A number near 1.8 on this page is square metres of estimated body surface, not a BMI and not a body-fat percentage. It does not establish whether someone is healthy or whether any treatment is appropriate.
Keeping area separate from treatment
A medical protocol may use BSA alongside drug-specific rules and other clinical information. This page does not supply a dose, choose a protocol or apply renal, hepatic, age or maximum-dose adjustments. Multiplying a BSA estimate by a number from an unrelated prescription is not a safe substitute for medication review. A prescriber or pharmacist must verify the intended equation and dosing protocol. Keep the displayed units attached to the result when sharing it.
Privacy and browser processing
Values entered on this page are processed in the current browser session. SolvePilot does not require an account and does not receive the values entered into the calculator. Refreshing or closing the page clears the working values unless the browser itself restores a previous session. Avoid entering identifying or account information because the calculation needs summary values only.
Accuracy and verification
Accuracy depends first on input quality. Confirm definitions, scales, dates and source information before entering a value. Keep an independent record of any result used for planning because this page does not create an official statement or retain a calculation history.
Limits of this estimate
Mosteller estimate only, without validation for individual clinical use. Does not diagnose, assess health or calculate medication doses.
Sources and review information
Frequently asked questions
How do I calculate BSA?＋
Enter measured centimetres and kilograms and click Calculate. Reproduce the equation by multiplying height and weight, dividing by 3,600 and taking the square root. The result is in square metres, which should stay attached to any saved value.
Which body surface area formula is used?＋
Only Mosteller is implemented. The formula is stated on the page so comparison with a chart using another method is transparent. The calculator does not silently switch formulas according to age or select whichever value happens to look more typical.
Is BSA the same as body-fat percentage?＋
No. BSA uses height and weight to estimate a geometric surface quantity. Body-fat methods use different measurements and equations. A BSA result cannot tell you how much fat a person has or distinguish muscle mass from fat mass.
Can this calculate a medicine dose?＋
No. The output is area only. A medication decision requires the exact protocol, clinical measurements, contraindications and professional verification. This calculator deliberately has no drug selection, dose recommendation or conversion from area into treatment instructions.
Why might my hospital report differ?＋
The clinical record may use another equation, older height and weight, different rounding or protocol-specific treatment of the value. Ask which formula was used and compare the same measurements. Do not assume the higher or lower number is automatically correct.