Enter Weight and Height
Example Data Table
| Case | Weight | Height | Mosteller BSA | Common Use Note |
|---|---|---|---|---|
| Infant example | 10 kg | 75 cm | 0.456 m² | Small body size review |
| Small adult | 50 kg | 160 cm | 1.491 m² | Lower adult range |
| Average adult | 70 kg | 175 cm | 1.845 m² | Common adult range |
| Larger adult | 90 kg | 180 cm | 2.121 m² | Higher adult range |
| Very large adult | 110 kg | 190 cm | 2.409 m² | Protocol review advised |
Formula Used
Body Surface Area is commonly reported in square meters. A weight-only estimate can be useful for screening, but height-weight formulas are usually preferred for adult review.
- Mosteller:
BSA = √((height cm × weight kg) / 3600) - 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 - Gehan and George:
BSA = 0.0235 × height cm^0.42246 × weight kg^0.51456 - Boyd:
BSA = 0.0003207 × height cm^0.3 × weight grams^(0.7285 - 0.0188 × log10(weight grams)) - Costeff:
BSA = ((4 × weight kg) + 7) / (weight kg + 90)
The selected result is shown first. The comparison table helps reveal how much the formulas differ.
How to Use This Calculator
- Enter the weight value and choose kilograms or pounds.
- Enter height in centimeters, meters, inches, or feet plus inches.
- Choose a preferred BSA equation from the formula list.
- Add an optional dose per square meter when needed.
- Select the decimal places for the final report.
- Press Calculate BSA to show the result above the form.
- Review the formula comparison table for variation.
- Download the CSV or PDF report for records.
Weight to BSA Conversion Guide
Why Body Surface Area Matters
Body surface area converts weight and height into one practical size estimate. It is widely used in clinical calculators, dose checks, renal indexing, burn review, and research records. A simple weight value alone can miss body shape. That is why this calculator also uses height. The result is shown in square meters.
How The Calculator Helps
The tool compares several accepted equations. It shows Mosteller, Du Bois, Haycock, Gehan and George, Boyd, and a weight only Costeff estimate. Each method can fit a different setting. Mosteller is simple and common. Du Bois is traditional. Haycock is often useful across wider body sizes. Seeing multiple values helps you notice variation before using the number.
Inputs And Units
You can enter weight in kilograms or pounds. You can enter height in centimeters, meters, inches, or feet with inches. The page converts every value internally before calculation. This keeps the output consistent. It also reduces manual conversion errors. Decimal control lets you choose a neat report value.
Dose Planning Support
Many medicines and treatments use a dose per square meter. This calculator includes an optional dose field. When you enter a dose rate, the page multiplies it by the selected BSA. This can support checking and documentation. It should not replace professional judgment, protocols, or patient specific review.
Interpreting Results
BSA is not the same as BMI. BMI compares weight with height squared. BSA estimates outer body area. Two people can have similar BMI values but slightly different BSA values. Hydration, edema, pregnancy, amputation, or extreme body size may affect interpretation. Always match the equation with your use case.
Export And Review
After calculation, you can save a CSV file. You can also download a simple PDF report. The example table shows typical cases and expected ranges. Use the saved output for notes, audit trails, teaching, or repeat comparisons. Recheck entries when a value looks unusual. Small unit mistakes can create large errors.
Keep clinical records aligned with local policy. Confirm rounding rules before medication use. For children, neonates, and oncology plans, use the equation required by the supervising protocol every time carefully.
FAQs
What is BSA?
Body Surface Area estimates the outer surface area of a person. It is usually shown in square meters and often uses height and weight together.
Can BSA be calculated from weight only?
A weight-only estimate exists, such as Costeff. It is rough. Height-weight formulas are usually better when height is available.
Which BSA formula should I use?
Mosteller is common and simple. Some settings require Du Bois, Haycock, Boyd, or another method. Follow your protocol first.
Why do formulas give different answers?
Each equation was developed from different data and assumptions. Differences are usually small, but they may matter in sensitive dosing work.
Does this calculator support pounds?
Yes. Enter weight in pounds and select the pound unit. The calculator converts it to kilograms before applying each formula.
Can I use the dose field for medicines?
The dose field multiplies dose per square meter by BSA. Use it for review only. Always confirm medication plans with approved guidance.
Is BSA the same as BMI?
No. BMI compares weight to height squared. BSA estimates body surface area. They answer different body measurement questions.
What export options are included?
The result card includes CSV and PDF download buttons. Use them to save values, formula comparisons, and report details.