Body Surface Area Calculator: method, checked example and practical limits
Estimate body surface area with the Mosteller height-and-weight formula. Square meters of estimated surface area differ from body mass, BMI and body-fat percentage.
Inputs used by this calculator
Body Surface Area Calculator uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Units | US — inches and pounds | US — inches and pounds · Metric — cm and kg | Selects the unit or conversion path used by Body Surface Area Calculator. |
| Height (inches or cm) | 67 | 20 to 275 | Supplies the height (inches or cm) quantity used by the published equation or result breakdown. |
| Weight (lb or kg) | 155 | 1 to 1000 | Supplies the weight (lb or kg) quantity used by the published equation or result breakdown. |
Inputs and measurement conventions
The quantities used on this page are Units, Height (inches or cm), Weight (lb or kg). Start with values for the same situation and read the units attached to each field. The field reference below shows supported choices and numerical limits.
Different accepted equations can produce different estimates. Dose calculations and pediatric decisions require the method specified by the clinical protocol.
Method and equation
Use the Mosteller square-root formula with height in centimeters and mass in kilograms to estimate adult body surface area.
Body Surface Area Calculator uses the following stated relationship: BSA=√(height cm×weight kg/3600). Its assumptions determine which question the answer can resolve.
BSA=√(height cm×weight kg/3600)Worked calculation with the starting values
Units: US — inches and pounds; Height (inches or cm): 67; Weight (lb or kg): 155. These starting values give 1.823063217 m² estimated body surface area. The calculation breakdown is Height (cm): 170.18; Weight (kg): 70.30681735; Mosteller product: 3.323559494.
At 170 cm and 70 kg, the Mosteller estimate is about 1.82 m².
Reading the answer
Square meters of estimated surface area differ from body mass, BMI and body-fat percentage.
Height (cm): 170.18; Weight (kg): 70.30681735; Mosteller product: 3.323559494. These intermediate quantities make the stated Body Surface Area Calculator model inspectable; they should be read together with the main answer rather than treated as independent guarantees.
Common errors and model boundaries
Different accepted equations can produce different estimates. Dose calculations and pediatric decisions require the method specified by the clinical protocol.
BSA is an estimate and medication dosing must follow the prescriber's protocol, patient data and clinical judgment.
Independent verification and next decision
No. The responsible clinician must select the equation and determine whether it fits the patient and treatment protocol.
For the Body Surface Area Calculator method, compare BSA=√(height cm×weight kg/3600) with the starting inputs and the calculation table. The linked Mosteller: simplified calculation of body surface area and Verbraecken et al.: comparison of adult body-surface-area formulas references identify the relevant definitions, conventions or domain limitations. Retain intermediate precision when comparing a manually worked answer.
Body Surface Area Calculator worked-example ledger
| Quantity | Example value | Role |
|---|---|---|
| Units | US — inches and pounds | Entered assumption |
| Height (inches or cm) | 67 | Entered assumption |
| Weight (lb or kg) | 155 | Entered assumption |
| Main answer | 1.823063217 m² estimated body surface area | Calculated from the starting inputs |
| Height (cm) | 170.18 | Intermediate or contextual output |
| Weight (kg) | 70.30681735 | Intermediate or contextual output |
| Mosteller product | 3.323559494 | Intermediate or contextual output |
Frequently asked questions
Can I use any BSA formula for treatment?
No. The responsible clinician must select the equation and determine whether it fits the patient and treatment protocol.
Which relationship does the Body Surface Area Calculator use?
Use the Mosteller square-root formula with height in centimeters and mass in kilograms to estimate adult body surface area. The displayed relationship is BSA=√(height cm×weight kg/3600).
What do the starting values produce in the Body Surface Area Calculator?
Units: US — inches and pounds; Height (inches or cm): 67; Weight (lb or kg): 155. These starting values give 1.823063217 m² estimated body surface area. The calculation breakdown is Height (cm): 170.18; Weight (kg): 70.30681735; Mosteller product: 3.323559494.
How should I interpret this Body Surface Area Calculator answer?
Square meters of estimated surface area differ from body mass, BMI and body-fat percentage.
Which input mistake most affects the Body Surface Area Calculator?
Different accepted equations can produce different estimates. Dose calculations and pediatric decisions require the method specified by the clinical protocol.
What is outside this Body Surface Area Calculator model?
BSA is an estimate and medication dosing must follow the prescriber's protocol, patient data and clinical judgment.
What to keep in mind
BSA is an estimate and medication dosing must follow the prescriber's protocol, patient data and clinical judgment.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.