BSA-Based Drug Dose
Some drugs, chemotherapy in particular, are dosed by body surface area rather than weight. This takes BSA by the Mosteller formula and multiplies by the unit dose.
Your numbers
Dose
165.8mg
Body surface area
1.658m²
Formula
Dose = √(Height (cm) × Weight (kg) ÷ 3600) × Dose (mg/kg)
Real doses follow the prescription and any renal or hepatic adjustment — use this only to check.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Height (cm)Height in centimetres; converted to metres inside the formula. | 165 | 30 ~ 250 |
| Weight (kg)The second weight you are comparing against. | 60 | 2 ~ 300 |
| Dose (mg/kg)How much drug is given per kilogram of body weight. | 100 | 0.1 ~ 2,000 |
Step by step
Quick reference table
Results when only Height (cm) changes and everything else stays put.
| Height (cm) | Dose (mg) | Body surface area (m²) |
|---|---|---|
| 82.5 | 117.3 | 1.173 |
| 124 | 143.8 | 1.438 |
| 165 | 165.8 | 1.658 |
| 248 | 203.3 | 2.033 |
| 250 | 204.1 | 2.041 |
What each result means
| Result | At default values |
|---|---|
| Dose (mg)How much drug goes in at one time. | 165.8 |
| Body surface area (m²)Body surface area — used for drug and fluid dosing. | 1.658 |
Common mistakes
Real doses follow the prescription and any renal or hepatic adjustment — use this only to check.
Glossary
- Height (cm)
- Height in centimetres; converted to metres inside the formula.
- Weight (kg)
- The second weight you are comparing against.
- Dose (mg/kg)
- How much drug is given per kilogram of body weight.
- Dose
- How much drug goes in at one time.
- Body surface area
- Body surface area — used for drug and fluid dosing.
Frequently asked questions
Q. How is BSA-Based Drug Dose calculated?
Dose = √(Height (cm) × Weight (kg) ÷ 3600) × Dose (mg/kg) — Some drugs, chemotherapy in particular, are dosed by body surface area rather than weight. This takes BSA by the Mosteller formula and multiplies by the unit dose.
Q. Can you walk through an example?
With Height (cm) 165, Weight (kg) 60, Dose (mg/kg) 100, the answer is Dose 165.8mg.
Q. What do I need to enter?
Enter Height (cm), Weight (kg), Dose (mg/kg). The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Height (cm) moves the answer to Height (cm) 82.5 → Dose (mg) 117.3 and Height (cm) 250 → Dose (mg) 204.1. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
Real doses follow the prescription and any renal or hepatic adjustment — use this only to check.
Related calculators
These calculators help you understand health figures; they do not replace diagnosis or prescription. See a clinician if you have symptoms.