Example 1
- Mass: 70 kg
- Height: 175 cm
1.84 / 1.85 m²
70 kg and 175 cm gives Mosteller 1.84 m² and Du Bois 1.85 m².
BSA calculator
Type mass and height. The calculator runs Mosteller and Du Bois side by side. Seventy kilograms and 175 cm are 1.84 m² and 1.85 m². Age and activity are optional if you want kcal per square meter.
Surface area from mass and height, two formulas side by side. BMI from the same two measurements is on the BMI calculator. This page does not multiply milligrams per m².
Result
Weight (kg), Height (cm), Age (years) and Sex. Mosteller BSA shows up here.
How it works
BSA estimates body surface from mass and height. Mosteller is the square root of (centimeters times kilograms over 3600). Du Bois is 0.007184 times cm to the 0.725 times kg to the 0.425. Seventy kilograms and 175 cm give 1.84 m² Mosteller and 1.85 m² Du Bois. Eighty kilograms and 180 cm give a clean 2.00 on both formulas. In adults the gap is often a few hundredths, but it does not always vanish: 100 kg at 185 cm is 2.27 versus 2.24.
People look up BSA because some doses are written per square meter. This page shows the meters. It does not multiply milligrams from a label and it does not replace a hospital drug card. Both formulas stay on the page so you can see that protocols pick a model. Skin is not one sacred constant.
Age, sex, and activity are optional. When you fill all three, the calculator runs Mifflin and TDEE, then divides by Mosteller and shows kcal per m² per day. Without those fields you just get two areas. Sex in the energy block does not enter Mosteller or Du Bois. BSA itself only knows kilograms and centimeters.
The US switch converts pounds and inches with 0.453592 and 2.54, then computes square meters. The formatter can show square feet, but the math still runs in cm and kg. Fifty-five kilograms and 160 cm give 1.56 m² on both formulas. Fifty kilograms and 155 cm is 1.47 m². Ninety kilograms and 190 cm is 2.18 m².
BMI divides mass by height squared and assigns a category. BSA estimates skin. Same two measurements, different formula, different meaning. Lorentz on the ideal-weight page returns kilograms from height and sex, with no area. None of those indexes is a dose.
Eighty-five kilograms and 170 cm split to 2.00 and 1.97. Sixty-five kilograms and 168 cm meet again at 1.74. Type mass and height, click Calculate, read both numbers. Treat them as body geometry for a class, not as a hospital order.
How to use
- Type mass and height in kilograms and centimeters, or in pounds and inches, matching the units switch.
- You can skip age, sex, and activity if you only want Mosteller and Du Bois.
- Fill that trio when you want a Mifflin and TDEE sketch divided by Mosteller BSA.
- Click Calculate. 70 kg and 175 cm give 1.84 m² Mosteller and 1.85 m² Du Bois. A few hundredths of difference is normal.
- Do not multiply the result by a dose from a label. These are square meters, with no milligrams per m².
Formula
BSAMosteller = √(cm × kg / 3600)
BSADu Bois = 0.007184 × cm0.725 × kg0.425
Optional kcal/m²/day = Mifflin or TDEE / Mosteller BSA. Not a drug dose.
Mosteller and Du Bois BSA in this calculator
Two surface-area formulas from mass and height. 70 kg and 175 cm are 1.84 m² (Mosteller) and 1.85 m² (Du Bois).
- BSA
- Body Surface Area in square meters. Here 70 kg and 175 cm print 1.84 and 1.85. Not a drug dose.
- Mosteller
- BSA = √(cm × kg / 3600). At 70 and 175 that is 1.84 m². Optional kcal/m² divides Mifflin or TDEE by this number.
- Du Bois
- BSA = 0.007184 × cm^0.725 × kg^0.425. The same 70 kg and 175 cm put 1.85 m² next to Mosteller.
Examples
Example 2
- Mass: 80 kg
- Height: 180 cm
2.00 / 2.00 m²
80 kg and 180 cm gives 2.00 m² in both formulas, about two square meters.
Example 3
- Mass: 55 kg
- Height: 160 cm
1.56 / 1.56 m²
55 kg and 160 cm gives 1.56 m² Mosteller and the same Du Bois.
Example 4
- Mass: 90 kg
- Height: 190 cm
2.18 / 2.18 m²
90 kg and 190 cm gives 2.18 m² in both formulas.
Example 5
- Mass: 100 kg
- Height: 185 cm
2.27 / 2.24 m²
100 kg and 185 cm gives 2.27 m² Mosteller and 2.24 m² Du Bois, so the formulas split.
Example 6
- Mass: 50 kg
- Height: 155 cm
1.47 / 1.47 m²
50 kg and 155 cm gives 1.47 m² in both formulas.
Example 7
- Mass: 85 kg
- Height: 170 cm
2.00 / 1.97 m²
85 kg and 170 cm gives 2.00 m² Mosteller and 1.97 m² Du Bois.
Example 8
- Mass: 65 kg
- Height: 168 cm
1.74 / 1.74 m²
65 kg and 168 cm gives 1.74 m² Mosteller and 1.74 m² Du Bois.
Frequently asked questions
Why are 70 kg and 175 cm 1.84 and 1.85, not one number?
The result is two formulas. Mosteller is the square root of cm times kg over 3600. Du Bois uses other exponents. In adults the gap is often hundredths.
Which formula is the “true” BSA at 100 kg and 185 cm?
Neither is a skin scan. On that pair Mosteller is 2.27 m² and Du Bois is 2.24 m². A hospital protocol picks the model. Here you see both.
Does this page give a dose per square meter?
No. It computes m². Milligrams per m² are multiplied on a drug card. This calculator does not do that multiply.
Are BMI and BSA the same thing from mass and height?
No. BMI is kg over meters squared and a category. BSA estimates surface. Same two measurements, different formula.
Why age and PAL if Mosteller ignores them?
Only for optional Mifflin and TDEE per m². You can skip them and keep the areas alone. Sex does not enter the BSA formulas themselves.
What do I get at 80 kg and 180 cm?
2.00 m² on both formulas. 90 kg and 190 cm also meet, at 2.18 m².
Do pounds and inches change 2.00 m² for the same person?
No, if you convert the same 80 kg and 180 cm with 0.453592 and 2.54. A different pound and inch pair is a different area.
Does a ft² readout mean a different formula?
No. The formatter can show square feet. The math still runs in cm and kg. The switch does not swap Mosteller out.
Does Lorentz from ideal weight replace BSA?
No. Lorentz gives kilograms from height and sex. BSA gives m² from mass and height. Different question, different number.
What is BSA at 55 kg and 160 cm?
1.56 m² on both formulas. 50 kg and 155 cm is 1.47 m². 65 kg and 168 cm is 1.74 m².
Knowledge sources
Surface area from mass and height. This page does not dose milligrams per m².
Page updated in 2026.