BSA Calculator (Mosteller, DuBois, Haycock, Boyd)
Calculate Body Surface Area using all 4 major formulas. Includes built-in mg/m² drug dose calculation for chemotherapy, pediatric dosing, and adult drug regimens.
Track every cycle of chemotherapy without spreadsheets
EasyClinic's longitudinal patient charts store every BSA, every cycle dose, every cumulative anthracycline exposure (lifetime cardiotoxicity threshold), and CrCl-adjusted carboplatin AUC dosing — purpose-built for oncology workflows.
Also Known As
What is Body Surface Area (BSA)?
Body Surface Area (BSA) is a measurement of the total surface area of the human body, expressed in square metres (m²). For an average adult, BSA ranges from 1.5–2.0 m². BSA correlates with metabolic mass and organ size, making it a more accurate basis for drug dosing than weight alone — especially for cytotoxic chemotherapy.
The Mosteller formula (BSA = √[height × weight / 3600]) is the most widely-used in clinical practice because of its simplicity and accuracy. It can be calculated on a basic calculator and gives results within ±5% of more complex formulas.
Common Drugs Dosed by BSA in India
- Chemotherapy: Cyclophosphamide, Doxorubicin, Paclitaxel, 5-FU, Methotrexate, Vincristine, Cisplatin, Etoposide, Gemcitabine, Pemetrexed
- Targeted therapy: Trastuzumab (8 mg/kg, then 6 mg/kg — by weight), Bevacizumab (by weight)
- Pediatric drugs: Some antiepileptics, immunosuppressants (cyclosporine, tacrolimus)
- Cardiac: Cardiac index (cardiac output / BSA), stroke volume index
Carboplatin uses Calvert formula (not flat BSA): Dose (mg) = AUC × (CrCl + 25). EasyClinic auto-calculates this when you select Carboplatin.
Frequently Asked Questions
▸Which BSA formula is most accurate?
For adults, all formulas give similar results (within ±5%). Mosteller is preferred for simplicity. For children <10 kg, Haycock is most accurate.
▸Should I use actual or ideal body weight for BSA?
Per ASCO 2012 guidelines, use actual body weight for BSA in chemotherapy — even in obese patients, do not cap the dose. Reducing chemo dose in obese patients leads to worse outcomes.
▸Why is BSA used instead of weight for chemotherapy?
Historically, BSA correlated better with hepatic and renal clearance of cytotoxic drugs. Modern PK/PD studies show this isn't always true, but BSA dosing remains the standard for most regimens.
▸How do I calculate BSA mentally for a quick estimate?
Quick rule: BSA ≈ √(weight in kg × height in cm / 3600). For a 70 kg, 170 cm adult: √(11900/3600) = √3.3 = 1.82 m².
▸Does BSA change with age?
Yes — BSA grows with age in children. Adult BSA stabilizes after late adolescence. Recalculate at every chemotherapy visit if patient gains/loses significant weight.
References
- Mosteller RD. Simplified Calculation of Body-Surface Area. NEJM 1987;317:1098
- DuBois D, DuBois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med 1916;17:863-71
- ASCO Guideline: Appropriate Chemotherapy Dosing for Obese Adult Patients with Cancer (2012)
Precision dosing, every time, automatically
EasyClinic auto-calculates BSA on patient registration and applies it to every mg/m² drug — chemotherapy regimens, pediatric drug doses, ANC tracking. No more manual recalculation per visit.