Inputs
This tool estimates BSA and calculates a dose based on common dosing patterns. It does not replace clinical judgment, labeling, protocols, or pharmacist review.
How to use this calculator
- Enter height and actual weight, then choose sex if using ideal or adjusted weight.
- Select the weight method and BSA formula required by your clinical protocol.
- Choose a dosing mode: BSA-based (mg/m²) or AUC-based (Calvert).
- Set rounding and optional caps only if specified by your regimen or pharmacy policy.
- Press Calculate to view results above the form and export if needed.
Formulas used
- Mosteller BSA: BSA (m²) = sqrt((Height(cm) x Weight(kg)) / 3600)
- DuBois BSA: BSA (m²) = 0.007184 x Height(cm)0.725 x Weight(kg)0.425
- Haycock BSA: BSA (m²) = 0.024265 x Height(cm)0.3964 x Weight(kg)0.5378
- Ideal Body Weight (Devine): Male = 50 + 0.9 x (cm-152.4), Female = 45.5 + 0.9 x (cm-152.4)
- Adjusted Body Weight: AdjBW = IBW + 0.4 x (Actual-IBW), when Actual > IBW
- BSA-based dosing: Dose (mg) = BSA (m²) x Dose intensity (mg/m²)
- AUC-based dosing (Calvert): Dose (mg) = Target AUC x (GFR + 25)
Example data table
Sample inputs and approximate outputs (for demonstration only).
| Height (cm) | Weight (kg) | Formula | Approx BSA (m²) | Dose Intensity (mg/m²) | Approx Dose (mg) |
|---|---|---|---|---|---|
| 170 | 70 | Mosteller | 1.818 | 50 | 90.9 |
| 160 | 60 | DuBois | 1.631 | 75 | 122.3 |
| 180 | 90 | Haycock | 2.087 | 40 | 83.5 |
Why body surface area matters in dosing
Body surface area (BSA) is often used to scale cytotoxic regimens because it reflects physiologic size better than weight alone. This calculator estimates BSA from height and a selected weight method, then converts a protocol dose intensity into milligrams. Adult BSA commonly falls near 1.6–2.2 m², so input changes can meaningfully shift dose clinically, especially across multiple cycles.
Choosing a BSA equation
Mosteller is popular for care because it is simple and consistent. DuBois and Haycock can differ slightly in extreme body sizes. Any percent change in BSA produces the same percent change in a BSA-based dose. When an institution specifies an equation, keep it consistent across visits to prevent unintended variability.
Weight selection, IBW, and adjusted weight
Protocols vary on whether actual, ideal, or adjusted weight should feed BSA. Ideal body weight (Devine) uses sex and height, while adjusted weight adds 40% of the excess above IBW. These options can support guidance for obesity, prior trial methods, or toxicity risk management. Follow regimen rules and pharmacist review for the final order.
Rounding and safety caps
Many pharmacies round doses to match vial sizes, compounding standards, or stability limits. The calculator rounds to a chosen step so you can preview how rounding affects the final value. Optional BSA and dose caps can model regimen limits. If a cap is applied, the displayed “used” value drives the computation. Record rounding and caps to support reproducible verification.
AUC-based dosing workflow
Some drugs, such as carboplatin, are dosed by target exposure rather than BSA. The AUC mode uses the Calvert relationship: dose equals target AUC multiplied by (GFR plus 25). Because renal estimates, units, and timing differ, confirm the GFR/CrCl method matches the protocol and use recent laboratory results when orders are checked and released.
FAQs
Use the formula specified by your institution or protocol. Mosteller is common in practice. Consistency across cycles is important because formula changes can shift BSA and therefore BSA-based doses.
Follow regimen guidance. Some protocols use actual weight, while others recommend ideal or adjusted weight in obesity or special populations. This tool shows all options so you can apply the correct rule.
It simulates pharmacy rounding to a practical increment, such as 1 mg, 5 mg, or 10 mg. Rounding policies depend on vial sizes, preparation standards, and institutional practices.
Only apply a cap if your protocol explicitly requires it. If used, the capped BSA is the value used for dose calculation and should be documented in the order verification notes.
AUC dosing targets drug exposure and typically uses renal function, not BSA. This calculator applies the Calvert relationship, which multiplies target AUC by (GFR plus 25), as specified by many carboplatin protocols.
No. Use it as a calculation aid. Final dosing must consider indication, labs, organ function, toxicity, labeling, and institutional protocols, and should be confirmed by qualified clinicians and pharmacists.