Body Surface Area Calculator - BSA & Army Body Fat Method

You're 170 lb and 5'9", and a clinician needs body surface area for dosing or charting. Mosteller gives about 1.9 m²; DuBois is close but not identical. Enter height and weight below for both BSA formulas, or switch to Army tape mode if you're tracking body fat percentage.

Average BSA
1.94 m²
DuBois & DuBois (1916)
1.93 m²
Mosteller (1987)
1.94 m²
Note: Body surface area is used in medical dosing calculations and burn assessments. Average adult BSA is approximately 1.7–2.0 m².

Methodology and limitations

Last reviewed:

Methodology

BSA mode uses DuBois & DuBois (1916) and Mosteller (1987) formulas. Army body fat mode uses US Army circumference method with logarithmic formulas from AR 600-9 and DoDI 1308.3.

Limitations

BSA formulas are clinical estimates for dosing and are not diagnostic. Army body fat method depends on correct tape placement and may be less accurate than DEXA or hydrostatic methods.

Official sources

How BSA and Army Body Fat Are Calculated

You're 170 lb and 5'9", and a clinician needs body surface area for dosing or charting. Mosteller gives about 1.9 m²; DuBois is close but not identical. Enter height and weight below for both BSA formulas, or switch to Army tape mode if you're tracking body fat percentage.

Method used

BSA mode calculates body surface area using DuBois & DuBois (1916) and Mosteller (1987) formulas for medical dosing. Army body fat mode uses US Army circumference method with AR 600-9 standards.

DuBois: BSA = 0.007184 × weight^0.425 × height^0.725; Mosteller: BSA = sqrt((height × weight) / 3600); Army BF: logarithmic formulas by sex from circumferences

Practical example

A 175 lb, 70-inch tall person has a BSA of approximately 1.95 m² (Mosteller). A male with 70" height, 15" neck, 34" waist has ~18% body fat by Army method.

  • BSA mode: weight and height
  • Army body fat mode: height, neck, waist, hip (females), age

BSA mode shows DuBois, Mosteller, and average BSA. Army mode shows body fat %, category, AR 600-9 standard, and meets-standard flag.

Assumptions

  • BSA formulas are clinical estimates for dosing.
  • Army method uses correct tape placement.
  • Standards vary by age and sex per AR 600-9.

What this includes

  • Two BSA formulas with average, Army body fat with standards, age-adjusted criteria, imperial and metric units.

What this excludes

  • DEXA or hydrostatic body fat, athlete body composition, burn severity TBSA, pediatric BSA adjustments, clinical diagnosis.

Frequently Asked Questions

What is body surface area (BSA) used for?

BSA is used in medical settings to calculate drug dosages, assess burn severity, and estimate cardiac index. It correlates body mass to metabolic rate better than weight alone.

Which BSA formula is more accurate?

Both DuBois and Mosteller are widely accepted. Mosteller is simpler and often preferred in clinical practice. This calculator shows both for comparison.

How does the US Army body fat method work?

The Army method uses circumference measurements and height in logarithmic formulas. Males use neck and waist; females add hip measurements. It is part of AR 600-9 fitness standards.

How do I measure my waist for Army body fat?

Males measure waist at navel level after a normal exhale. Females measure at the narrowest point. Keep the tape snug but not compressing the skin.

Are Army body fat standards the same for all ages?

No. AR 600-9 and DoDI 1308.3 allow higher body fat percentages for older service members. Standards range from 20–26% for males and 30–36% for females by age bracket.