Body Fat Percentage & Healthy Weight Range Calculator
Estimate your body fat percentage using the U.S. Navy circumference method and determine your healthy weight range based on BMI guidelines (18.5–24.9).
Formulas Used
U.S. Navy Body Fat Percentage (circumference method):
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
All measurements in centimetres.
BMI: BMI = weight (kg) ÷ height² (m²)
Healthy weight range: weight = BMI × height² (m²), for BMI 18.5–24.9
Fat mass: Fat Mass = body weight × (BF% ÷ 100)
Lean mass: Lean Mass = body weight − Fat Mass
Assumptions & References
- Body fat is estimated using the U.S. Navy circumference method (Hodgdon & Beckett, 1984), validated against hydrostatic weighing.
- Waist is measured at the navel (men) or narrowest point (women); neck just below the larynx; hips at the widest point (women only).
- Healthy weight range is based on a BMI of 18.5–24.9 (WHO / NIH guidelines).
- Body fat categories follow American Council on Exercise (ACE) guidelines.
- This calculator is for informational purposes only and does not replace professional medical advice.
- The Navy method has a typical error of ±3–4 percentage points compared to DEXA or hydrostatic weighing.
- BMI does not account for muscle mass, bone density, or fat distribution; use alongside BF% for a fuller picture.