| Formula | BSA (m²) | Copy |
|---|---|---|
| {{ r.name }} | {{ format(r.value) }} |
Body surface area (BSA) is an estimate of the total external area of a human body used to calibrate drug dosing and physiological indexes. Many clinicians run a body surface area formulas comparison to check consistency before acting. Each method combines height and weight differently, which can shift treatment thresholds by a few percent. When methods disagree slightly, the context and regimen usually matter more than the last decimal.
You provide height and weight, and the engine returns body surface area from five validated formulas plus the arithmetic mean. Values use your chosen units and can be compared side by side without extra conversions. You can highlight one formula, view its index versus the mean, and if you enter a dosing rate the tool multiplies by BSA to show a single milligram total that you can export as CSV or JSON.
For example, a person 170 cm tall and 65 kg produces a BSA near 1.75 m² by Mosteller, with other methods within about 1–2%. That small spread is normal and reflects how each equation weights height and mass. Treat the rounded display as a guide, not a rule. This tool provides informational estimates and does not substitute professional advice.
You can cap BSA when protocols call for a ceiling, choose display precision to match local practice, and export the full set for audit. For consistent results, measure standing height without shoes and current weight, then keep units steady across visits. In pediatric or extreme body sizes, compare the mean and the individual equations before using any dose.
Body surface area combines stature and mass to estimate external area. This implementation computes BSA with five published equations and converts units as needed. Heights are converted to centimetres and metres where required; weights to kilograms and grams for specific equations. Outputs include the five BSA values, their arithmetic mean, a selected method, an index versus the mean, and an optional cap applied to the selected value. A dosing helper multiplies effective BSA by a regimen in milligrams per square metre and rounds to the nearest milligram. Operations are deterministic and run entirely in the browser.
| Symbol | Meaning | Unit/Datatype | Source |
|---|---|---|---|
h_cm | Body height | cm | Input |
h_m | Body height | m | Derived |
w_kg | Body weight | kg | Input |
w_g | Body weight | g | Derived |
BSA | Body surface area | m² | Derived |
mean | Arithmetic mean of all BSA values | m² | Derived |
index | Selected BSA ÷ mean × 100 | % | Derived |
dose | Total dose | mg | Derived |
| Field | Type | Min | Max | Step/Pattern | Error Text | Placeholder |
|---|---|---|---|---|---|---|
| Height value | number | 0 | — | — | Browser default | None |
| Height unit | select | — | — | cm · m · in | — | — |
| Weight value | number | 0 | — | — | Browser default | None |
| Weight unit | select | — | — | kg · lb | — | — |
| Formula | select | — | — | Mosteller · Du Bois · Haycock · Gehan & George · Boyd | — | — |
| Cap BSA at | number | 0 | — | step 0.01 | Browser default | None |
| Dose per m² | number | 0 | — | step 0.1 | Browser default | None |
| Round BSA to | range | 0 | 5 | step 1 | — | — |
Math.round rule (0.5 rounds toward +∞).| Input | Accepted Families | Output | Encoding/Precision | Rounding |
|---|---|---|---|---|
| Height, Weight, Units, Formula | Numeric fields; unit selectors | Five BSA values, mean, index | Double precision; period decimal | Display 0–5 dp; internal full precision |
| Cap, Dose per m² | Non‑negative numbers | Effective BSA; total dose | Double; dose as integer mg | Cap is a hard ceiling; dose uses nearest mg |
| CSV export | Table snapshot | Formula,BSA (m²) |
Comma‑separated text | Values at engine precision |
| JSON export | Inputs and outputs | {inputs:{…},outputs:{…}} |
2‑space indentation | No forced rounding in payload |
Inputs: height 170 cm; weight 65 kg; rounding 3 dp; no cap; dose 150 mg/m².
Results:
Numbers are rounded for display; exports include full‑precision values where available.
Formulas reflect work by Mosteller; Du Bois and Du Bois; Haycock and colleagues; Gehan & George; and Boyd. These are widely cited in clinical dosing and physiology. Choose methods according to local protocol and patient context.
Processing is browser‑based only. No data is transmitted or stored server‑side. Use exports responsibly under applicable privacy regulations.
Enter measurements, pick a formula, and optionally add dosing and rounding.
Example: 170 cm, 65 kg, Mosteller, cap 0, dose 150 mg/m² → dose 263 mg.
You now have side‑by‑side values for review, charts for context, and exports for records.
Mosteller, Du Bois, Haycock, Gehan & George, and Boyd. You can compare all five side by side and see their arithmetic mean.
Expect small differences across equations, often within a few percent. BSA guides decisions but does not replace clinical judgment or protocol.
Yes. Height accepts cm, m, or in; weight accepts kg or lb. The engine converts units internally before computing BSA.
Dose equals effective BSA multiplied by your mg/m² regimen, rounded to the nearest milligram. Set a cap if your protocol requires a ceiling.
No. Calculations, charts, clipboard actions, and downloads are handled in your browser without server storage.
Once loaded, calculations run in the browser. No sign‑in is required.
Some protocols limit BSA to reduce toxicity risk at high body sizes. Use caps only when a guideline specifies a value.
Enter measurements, then switch the highlighted method. Use the Δ% chart to see each equation’s deviation from the mean at a glance.