Measure waist circumference (at the level of the iliac crest or midway between lowest rib and top of hip bone)
Measure height
Use a body fat formula based on the method you choose (examples below)
US Navy method (common for adults)
Male: %BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Female: %BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
Inputs (in same units): waist, neck, height (and hip for females)
Use log10
YMCA method (requires multiple measurements)
Take: height, weight, neck, waist, and hip (for women)
Use the YMCA body fat equation for your sex:
Male: %BF = 1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height) − 0.00067546 × (age)
Female: %BF = 1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height) − 0.0008192 × (age)
Use log10
Inputs (in same units): waist, neck, hip (if applicable), height; include age
Calipers (skinfold thickness)
Measure skinfolds with calipers (commonly 3-site or 7-site protocols)
Convert summed skinfolds to body density using the Jackson–Pollock equation (or another validated equation)
Convert body density to %BF using: %BF = (495 / body density) − 450
Follow the exact site locations, equation, and sex-specific constants
Body mass index (BMI) method (rough estimate; not precision)
Compute BMI = weight / height²
Use a population-specific regression or table to estimate %BF (varies by sex and ethnicity)
Record the resulting %BF from the chosen reference
Bioelectrical impedance analysis (BIA) method
Use a BIA scale/device
Enter required fields (sex, age, height, sometimes activity level)
Ensure consistent conditions (hydration, time since exercise, food intake)
Read %BF directly from the device output
DEXA method
Use a DEXA scan
Use the scan-reported % body fat directly