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Body Surface Area Calculator
Estimate body surface area from height and weight using the Mosteller formula, a common clinical method for BSA calculation.
Body surface area
2.01 m²
Square feet
21.61 ft²
EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.
Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.
Learn more about our review process on the EveryCalc methodology page.
How this calculator works
What this page estimates
This Body Surface Area Calculator is built to give a quick, browser-based estimate for body surface area. Estimate body surface area from height and weight using the Mosteller formula, a common clinical method for BSA calculation. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.
Calculation approach
The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For health tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.
Example workflow
For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.
Practical checks
- Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
- Run a low, base, and high case when the inputs are estimates.
- Check the related calculators below when the next decision depends on a different assumption.
How to interpret the body surface area result
Best use
Use the result as an informational wellness estimate that can help organize measurements, targets, or timing before a conversation with a clinician.
Cross-check
Compare the output with your own records, device readings, lab values, medication instructions, or guidance from a qualified health professional.
Watch for
Do not use this page to diagnose, treat, or ignore symptoms. Health calculators are most useful when they make questions clearer, not when they replace care.
This page belongs to the Health calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.
Before relying on this body surface area estimate
Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.
Use current measurements
Recent weight, height, age, activity, nutrition, sleep, or timing inputs matter more than remembered estimates.
Look for context
A calculator can organize a wellness number, but it cannot read symptoms, medical history, medications, or lab results.
Escalate high-impact questions
Use clinical guidance for pregnancy, dosage, heart, risk, illness, or treatment decisions.
Rerun this page when measurements change, a clinician gives new guidance, or the result is being used for a new goal.
How to Use
- Enter body weight in pounds and height in feet and inches so the calculator can estimate overall body size using the standard Mosteller approach.
- Review the result in square meters first, because that is the unit most often used when BSA appears in medical and reference contexts.
- Use the square-feet value only as a secondary reference if that unit is easier for your own comparison or documentation needs.
- Treat the result as an estimate of body size, not a measure of health, body fat, or fitness. BSA answers a different question than BMI or body composition tools.
- If you are using BSA as part of a clinical decision, medication discussion, or treatment plan, confirm the inputs and follow professional guidance rather than relying on a quick estimate alone.
Frequently Asked Questions
What is body surface area?
Body surface area estimates the total external surface of the human body, usually expressed in square meters. It is a size-based metric rather than a health score.
Why is BSA used?
BSA is used in some clinical settings, research references, and body-size comparisons where total surface area is more relevant than body weight alone. It is one of several ways to normalize measurements across differently sized people.
Which formula does this calculator use?
This calculator uses the Mosteller formula, a widely used method because it is simple, fast, and generally practical for routine estimation from height and weight.
Is BSA the same as BMI?
No. BMI relates weight to height and is often used as a rough weight-status screening tool, while BSA estimates body surface area. The two measurements are not interchangeable.
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