Body Surface Area (BSA) Calculator

Height + weight · Mosteller 1987

Body Surface Area (BSA) Calculator

Choose the units on your measurements, enter height and weight, and calculate an estimated surface area in square meters.

MethodMostellerOne fixed formula

Mosteller BSA method and medication boundary

Calculate Mosteller body surface area, then stop before making a dose decision

Body surface area is an estimate derived from height and weight. This page implements only the Mosteller equation and exposes normalized metric inputs so the arithmetic can be checked, while keeping prescribing, preparation, and administration firmly outside the calculator.

Step-by-step guide · Mosteller BSA method and medication boundary

Normalize customary inputs before touching the radical

Named method: Mosteller BSA is the square root of height-cm times weight-kg divided by 3,600.
Reported unit: The result is an estimated surface area in square meters.
Safety limit: A BSA value alone never authorizes a medication or chemotherapy dose.

Assemble total height
Convert feet and remaining inches into total inches, then multiply by exactly 2.54 centimeters per inch. Keep the inches field below 12 rather than entering a second feet value there.
Convert mass exactly
Multiply avoirdupois pounds by exactly 0.45359237 kilograms per pound. Do not use the shortcut of dividing by 2.2 when trying to reproduce a clinical system.
Inspect normalized values
Confirm that the displayed centimeters and kilograms match the source measurements before accepting the square root. A unit slip can look numerically plausible after aggregation.

Calculate Mosteller body surface area, then stop before making a dose decision: The tool follows one metric calculation path even when feet, inches, and pounds are entered.

Mosteller compresses two measurements into one square-root estimate

The equation is BSA in square meters = sqrt(height in centimeters × weight in kilograms / 3,600). For 170 centimeters and 60 kilograms, the value under the root is 2.8333..., producing about 1.683 square meters. Preserve the input conversion and the radicand until the final display; repeated intermediate rounding can create avoidable differences between systems.

Mosteller is one named formula, not a direct scan of the skin or a universal physiological measurement. Other BSA equations can return different values for the same person. If the task is a height-to-weight index rather than surface area, use the Adult BMI Calculator. If a protocol names a BSA method, the named method controls; this page must not be used to silently substitute Mosteller for another specified equation.

Normalize customary inputs before touching the radical

The tool follows one metric calculation path even when feet, inches, and pounds are entered.

Assemble total height
Convert feet and remaining inches into total inches, then multiply by exactly 2.54 centimeters per inch. Keep the inches field below 12 rather than entering a second feet value there.
Convert mass exactly
Multiply avoirdupois pounds by exactly 0.45359237 kilograms per pound. Do not use the shortcut of dividing by 2.2 when trying to reproduce a clinical system.
Inspect normalized values
Confirm that the displayed centimeters and kilograms match the source measurements before accepting the square root. A unit slip can look numerically plausible after aggregation.

Distinguish a protocol input from an independent prescription

The same BSA number can appear in a legitimate clinical workflow or in an unsafe shortcut.

Protocol-bound use

A qualified team may verify current height, weight, the mandated BSA equation, drug label or protocol, dose caps, organ function, and patient-specific modifications. Independent checks remain part of the workflow.

Arithmetic practice

The Dosage Calculation Calculator can help reproduce separately supplied dimensional arithmetic, but neither page creates a valid order or chooses a medicine.

Unsafe inference

Multiplying an online BSA by a dose found on the internet and treating the product as instructions skips diagnosis, prescription, protocol selection, caps, contraindications, verification, and professional oversight.

A reproducible number is not a diagnosis or clinical clearance

BSA does not diagnose cancer, infection, kidney disease, toxicity, or any other condition. It cannot determine whether treatment is indicated. Children, pregnancy, edema, amputation, extreme body size, or rapid body-size change can raise additional measurement and method questions that the two-input formula does not resolve.

The result also says nothing about kidney clearance. When a clinician has ordered a separate renal estimate, the Creatinine Clearance Calculator addresses its own bounded equation and inputs; it must not be inferred from BSA. Separate clinical variables remain separate because each carries distinct assumptions and safety checks.

Apply a hard medication stop after the calculation

These limits matter even when the square-root arithmetic is correct.

Never use this result to diagnose, prescribe, select, start, stop, prepare, alter, or administer a drug, and never self-calculate a chemotherapy dose.
Do not turn BSA into an infusion rate or use it to derive ordered volume-and-time arithmetic. An infusion calculation cannot supply or validate a clinical order.
For any real medication workflow, use current verified measurements, the current label and institutional protocol, a valid prescription, applicable caps and adjustments, and independent pharmacist or clinician verification.

Important limitations

This height-and-weight estimate is not a direct body measurement, diagnosis, treatment plan, or medication-dosing instruction. Confirm the required BSA method and current measurements for any clinical workflow.

Review the stated scope, calculation method, assumptions, supported inputs, and effective dates, and obtain qualified advice before using a high-stakes result.

This formula passed its registered engineering tests and is published under an explicit site-owner policy authorization. No independent expert, QA, editorial, legal, or third-party review is claimed. Verify consequential results with a qualified professional.

This subject may affect health, finance, tax, legal, or other consequential decisions. It has not received an independent domain-expert review; consult a qualified professional before relying on it.

Mosteller BSA method and medication boundary

Calculate Mosteller body surface area, then stop before making a dose decision

Step-by-step guide · Mosteller BSA method and medication boundary

Normalize customary inputs before touching the radical

Named method: Mosteller BSA is the square root of height-cm times weight-kg divided by 3,600.
Reported unit: The result is an estimated surface area in square meters.
Safety limit: A BSA value alone never authorizes a medication or chemotherapy dose.

Assemble total height
Convert feet and remaining inches into total inches, then multiply by exactly 2.54 centimeters per inch. Keep the inches field below 12 rather than entering a second feet value there.
Convert mass exactly
Multiply avoirdupois pounds by exactly 0.45359237 kilograms per pound. Do not use the shortcut of dividing by 2.2 when trying to reproduce a clinical system.
Inspect normalized values
Confirm that the displayed centimeters and kilograms match the source measurements before accepting the square root. A unit slip can look numerically plausible after aggregation.

Calculate Mosteller body surface area, then stop before making a dose decision: The tool follows one metric calculation path even when feet, inches, and pounds are entered.

Mosteller compresses two measurements into one square-root estimate

Normalize customary inputs before touching the radical

The tool follows one metric calculation path even when feet, inches, and pounds are entered.

Assemble total height
Convert feet and remaining inches into total inches, then multiply by exactly 2.54 centimeters per inch. Keep the inches field below 12 rather than entering a second feet value there.
Convert mass exactly
Multiply avoirdupois pounds by exactly 0.45359237 kilograms per pound. Do not use the shortcut of dividing by 2.2 when trying to reproduce a clinical system.
Inspect normalized values
Confirm that the displayed centimeters and kilograms match the source measurements before accepting the square root. A unit slip can look numerically plausible after aggregation.

Distinguish a protocol input from an independent prescription

The same BSA number can appear in a legitimate clinical workflow or in an unsafe shortcut.

Protocol-bound use

Arithmetic practice

The Dosage Calculation Calculator can help reproduce separately supplied dimensional arithmetic, but neither page creates a valid order or chooses a medicine.

Unsafe inference

A reproducible number is not a diagnosis or clinical clearance

Apply a hard medication stop after the calculation

These limits matter even when the square-root arithmetic is correct.

Never use this result to diagnose, prescribe, select, start, stop, prepare, alter, or administer a drug, and never self-calculate a chemotherapy dose.
Do not turn BSA into an infusion rate or use it to derive ordered volume-and-time arithmetic. An infusion calculation cannot supply or validate a clinical order.
For any real medication workflow, use current verified measurements, the current label and institutional protocol, a valid prescription, applicable caps and adjustments, and independent pharmacist or clinician verification.

Body Surface Area (BSA) Calculator