Calculator
What the Body Surface Area Calculator does
Body Surface Area Calculator: calculates Body Surface Area (m²) from Weight and Height. Example: weight 70 kg and height 170 cm gives body surface area (m²) 1.82.
The Body Surface Area Calculator turns Weight and Height into Body Surface Area (m²). Adjust anything and the figures re-derive on the spot.
Most people who open the Body Surface Area Calculator are readers checking a number from a clinic. Knowing how a figure is derived makes it much easier to interpret sensibly.
The work is done by JavaScript already loaded in your browser, so your input never crosses the network.
Everything needed to verify a result is further down: the fields, the method and one fully worked example.
What do the Body Surface Area Calculator fields mean?
The Body Surface Area Calculator uses 2 inputs. A filled form means you can test one idea immediately instead of sourcing every input first.
| Field | What to enter | Default |
|---|---|---|
| Weight | measured in kg; accepts 1 to 300 | 70 |
| Height | measured in cm; accepts 40 to 250 | 170 |
How does the Body Surface Area Calculator work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same calculation.
Bad input produces an error, never a confident-looking wrong answer.
Worked example
These are the values the Body Surface Area Calculator loads by default, and the result it produces from them. Below is the same computation the tool performs on load, step by step.
| Weight | 70 kg |
|---|---|
| Height | 170 cm |
| Body Surface Area (m²) | 1.82 |
|---|---|
| What this means | BSA ≈ 1.82 m² (Mosteller). Often used for medication dosing: follow clinical guidance. |
Read next: Understanding BMI: What the Number Measures, and What It Misses
How to use it
- Key in Weight in kg (1 to 300).
- Fill in Height in cm (40 to 250).
- No confirmation step: what you type is what gets calculated.
- Read Body Surface Area (m²) and What this means in the results panel.
- Copy Link when you want to return to this exact configuration; Print when someone needs it on paper.
What this tool does not do
- Body composition, ethnicity and age all shift what a "normal" result means for an individual.
- Population-level formulas cannot account for medical conditions, medication or pregnancy.
- It handles the common case well and the unusual case literally.
- A number that passes validation has been checked for plausibility, not for correctness.
Frequently asked questions
Enter Weight in kg and Height in cm. Each field states its unit next to the input, and outputs are labelled the same way.
Weight accepts 1 to 300 kg. The range is enforced before the calculation runs, so a bad entry never reaches the formula.
With the values loaded when the page opens, body surface area (m²) comes out as 1.82. Adjust any field to see how much the answer depends on it.
No. The work runs in JavaScript inside this page, so your values never leave your device. You can confirm it in your browser network tab.
No charge. Everything on the page is available without signing in.
The computation is exact. What it is computing is a population average, which is a different thing from a fact about you, so read the number as a prompt to ask a better question.