Results
Body Fat %: –
Fat Mass: –
Lean Mass: –
Classification: –
Age-Based Interpretation: –
📘 Overview: Estimate Body Fat the Reliable Way
This Body Fat Percentage Calculator uses the official U.S. Navy Method to estimate your body fat percentage based on your gender, height, neck, waist, and hip measurements. Unlike BMI, it accounts for individual body composition and fat distribution.
The tool also computes your fat mass and lean mass based on total weight, and categorizes your body fat according to fitness and age-based standards.
- 🔢 Supports both metric (cm/kg) and imperial (in/lbs) units
- ⚖️ Displays body fat %, fat mass, lean mass
- 📊 Classifies body fat level (essential, fitness, average, obese)
- 📅 Age-based categories for men and women
🧮 Formula & Methodology
Based on logarithmic formulas used by the U.S. Navy for body composition assessments:
Men:
BF% = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76
Women:
BF% = 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387
These equations estimate your body fat percentage by analyzing circumferences and height, which correlate with body composition. Final values are then used to compute fat mass (BF% × weight) and lean mass.
📊 Examples
- Male: 180 cm height, 90 cm waist, 40 cm neck, 80 kg → ~18.5% body fat, 14.8 kg fat mass
- Female: 165 cm height, 75 cm waist, 35 cm neck, 95 cm hip, 70 kg → ~26.2% body fat, 18.3 kg fat mass
These examples help visualize what your results mean in practical, health-related terms.
💡 Use Cases
- 🏋️♀️ Track fat loss or muscle gain during fitness plans
- 🧮 Estimate ideal lean mass for training or diet goals
- 📉 Monitor health risks tied to excess body fat
- 📅 Periodically check changes after workouts or meal plans
- 👩⚕️ Use as a screening tool for wellness coaching or physical exams
📚 Body Fat Classification Ranges
Men:
- 2–5% → Essential fat
- 6–13% → Athletes
- 14–17% → Fitness
- 18–24% → Average
- 25%+ → Obese
Women:
- 10–13% → Essential fat
- 14–20% → Athletes
- 21–24% → Fitness
- 25–31% → Average
- 32%+ → Obese
❓ Frequently Asked Questions
Why is body fat % more useful than BMI?
Unlike BMI, which only considers weight and height, body fat % reflects actual body composition. It’s a better metric for assessing fitness, especially for muscular individuals.
Why is my weight required?
Your total body weight is used to calculate absolute fat mass and lean mass, which are helpful for setting health or performance goals.
Why is hip measurement only required for women?
Women naturally store more fat around the hips and thighs. The Navy formula accounts for this by including hip circumference in the female equation.
Can I use this calculator to set weight goals?
Yes! Once you know your current fat % and lean mass, you can estimate how much weight you’d need to lose or gain to reach a target body fat %.
How accurate is the U.S. Navy method?
It’s reasonably accurate (±3–4%) when measurements are taken consistently. For clinical use, more advanced methods like DEXA or hydrostatic weighing are recommended.
Is this suitable for children or teens?
No. This calculator is intended for adults aged 18 and over. For teens, use our BMI-for-Age Calculator.
How do I take accurate measurements?
Use a flexible tape. Neck: just below Adam’s apple. Waist: at navel. Hips (women): widest point. Don’t suck in or hold your breath.