Mr Calcu | Quickly find the right drug dose with our BSA calculator—built for accuracy, speed, and confidence at the point of care.

Calculate precise drug dosages using BSA. Empower care decisions and reduce risk with this fast, trusted tool for patients and professionals alike.

BSA Drug Dosage Calculator

Metric

Imperial

Height (cm)

Weight (kg)

Dosage per BSA (mg/m²)

Body Surface Area Drug Dosage Calculator Guidelines

Get accurate results in seconds—just follow these steps:

Usage Instructions

Step 1: Enter the patient's height and weight in metric units (cm and kg).
Step 2: Ensure units are consistent—use a reliable conversion if starting with imperial values.
Step 3: Enter the medication’s recommended dose per square meter (mg/m²).
Step 4: Click Calculate to compute the BSA and total dosage.

Clinical Notes

Review extreme BSA values carefully—values below 0.5 m² or above 2.5 m² may require adjusted formulas or clinical input.
Consider renal and hepatic function before administering the calculated dose.
Use the Du Bois or Haycock formulas in pediatric or research settings if required.

Body Surface Area Drug Dosage Calculator Description

What is Body Surface Area (BSA)?

Body Surface Area (BSA) is used to calculate more personalized drug dosages, especially for treatments in oncology, pediatrics, and nephrology. Unlike weight alone, BSA accounts for a patient's body geometry and surface metabolism.

Why Use BSA for Drug Dosing?

More accurate dosing for chemotherapy and toxic drugs
Better reflects metabolic mass than weight alone
Reduces risk of under- or overdosing in extreme body sizes

Standard Formula Used

The Mosteller formula is commonly used in clinical practice due to its simplicity:

BSA (m²) = √( [Height(cm) × Weight(kg)] / 3600 )

Other formulas that may be used in specific populations:

Du Bois: BSA = 0.007184 × Height(cm)^0.725 × Weight(kg)^0.425
Haycock: BSA = 0.024265 × Height(cm)^0.3964 × Weight(kg)^0.5378

Pro Tip: Always double-check extreme BSA values (below 0.5 or above 2.5 m²). These may indicate data entry errors or special clinical considerations.

How Drug Dosage is Determined

Once BSA is known, calculate the medication dosage as:

Dosage (mg) = BSA (m²) × Recommended Dose (mg/m²)

Edge Cases to Watch

Obese patients: May require adjusted BSA or capped dosing.
Underweight/cachectic patients: Risk of toxicity even at standard BSA doses.
Children and infants: May need further corrections due to immature organ function.
Extremely tall or short individuals: Outliers can distort results—use clinical judgment.
Organ dysfunction: BSA should be used alongside renal/hepatic clearance monitoring.

Case Studies

Case 1: Pediatric Oncology

Patient: 5-year-old, 110 cm, 18 kg
Drug: 25 mg/m²
BSA: √(110 × 18 / 3600) ≈ 0.741 m²
Dosage: 0.741 × 25 = 18.53 mg

Case 2: Obese Adult Oncology

Patient: 42-year-old, 165 cm, 120 kg
Drug: 50 mg/m²
BSA: √(165 × 120 / 3600) ≈ 2.345 m²
Dosage: 2.345 × 50 = 117.25 mg

Note: Always refer to your institutional protocol for maximum dosing thresholds.

Start using the BSA calculator now to improve accuracy, reduce risk, and make faster, smarter dosing decisions.

Example Calculation

Height (cm)	Weight (kg)	BSA (m²)	Dosage (mg)
170	60	1.70	340
180	80	2.00	400
110	18	0.74	18.5
165	120	2.35	117.3
150	35	1.14	57

Frequently Asked Questions

BSA is the calculated surface area of a person's body, used in medical dosing to standardize drug administration across patients of varying sizes.

BSA is more closely correlated with metabolic rate and organ function than body weight, making it a better predictor for appropriate drug levels in certain therapies.

No. While useful in many scenarios, BSA may not be ideal for all patients. Adjustments or alternative methods may be needed in obesity, cachexia, or renal failure cases.

Yes. Mosteller, Du Bois, Haycock, and others can produce slightly different BSA estimates. Clinical context determines the best choice.

Convert to kilograms and centimeters before using the calculator. The Mosteller formula specifically requires metric units for accuracy.

Clinically, BSA values below 0.5 m² or above 2.5 m² should prompt re-checks and possible clinician review, as these may indicate measurement or entry errors.

BSA dosing is a widely accepted standard for chemotherapy, though recent research suggests that pharmacokinetics and organ function should also be considered for maximum accuracy.

Mr Calcu | Quickly find the right drug dose with our BSA calculator—built for accuracy, speed, and confidence at the point of care.

BSA Drug Dosage Calculator

Body Surface Area Drug Dosage Calculator Guidelines

Usage Instructions

Clinical Notes

Body Surface Area Drug Dosage Calculator Description

What is Body Surface Area (BSA)?

Why Use BSA for Drug Dosing?

Standard Formula Used

How Drug Dosage is Determined

Edge Cases to Watch

Case Studies

Case 1: Pediatric Oncology

Case 2: Obese Adult Oncology

Example Calculation

Frequently Asked Questions

What is Body Surface Area (BSA)?

Why is BSA used in drug dosage?

Is BSA always the best method for drug dosing?

Can different formulas yield different BSA values?

What if the patient's measurements are in pounds and inches?

Is there a maximum or minimum BSA limit?

How accurate is BSA-based dosing for chemotherapy?

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