Body Fat Calculator
Estimate your body fat percentage using the US Navy method. Just a few tape measure readings — no calipers needed.
How to use this calculator
Select your gender, then set your height with the sliders. Take three measurements with a flexible tape measure: waist (at the navel for men, narrowest point for women), neck (just below the Adam's apple), and hip (widest point — women only). Measure in the morning before eating, standing relaxed. Optionally enter your weight to also see your fat mass and lean mass breakdown.
Understanding your body fat percentage
The US Navy method is one of the most practical ways to estimate body fat at home — no special equipment needed, and it's accurate to within 3-4% for most people. Essential fat is the minimum needed for basic body functions. Athlete ranges are typical for competitive athletes. Fitness ranges indicate a lean, active physique. Average ranges are healthy. Results above 25% for men or 32% for women indicate elevated health risk.
Frequently asked questions
Body fat percentage categories
Body fat categories differ by sex because women carry more essential fat for reproductive function. The ranges below are from the American Council on Exercise (ACE) and are widely used in fitness and clinical settings.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 – 5% | 10 – 13% |
| Athletes | 6 – 13% | 14 – 20% |
| Fitness | 14 – 17% | 21 – 24% |
| Acceptable (average) | 18 – 24% | 25 – 31% |
| Obese | ≥ 25% | ≥ 32% |
How the US Navy body fat formula works
The Navy method uses circumference measurements and height to estimate body fat percentage. It was developed by Hodgdon and Beckett (1984) and is used by the US military for fitness assessments. The formulas use logarithms to account for fat distribution patterns.
| Sex | Formula |
|---|---|
| Male | BF% = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76 |
| Female | BF% = 163.205 × log₁₀(waist + hips − neck) − 97.684 × log₁₀(height) − 78.387 |
Body fat measurement methods compared
Several methods exist for measuring body fat, with widely varying accuracy, cost, and accessibility. The Navy method is an excellent free option for tracking trends at home.
| Method | Accuracy | Cost | Notes |
|---|---|---|---|
| DEXA scan | ±1–2% | $50–150 | Gold standard; measures bone, muscle, and fat separately |
| Hydrostatic weighing | ±2–3% | $30–75 | Highly accurate; requires full body immersion in water |
| Air displacement (Bod Pod) | ±2–3% | $45–100 | Accurate; less common availability |
| Skinfold calipers | ±3–5% | $10–30 | Accuracy depends heavily on technician skill |
| Navy circumference method | ±3–4% | Free | Easy to do at home; accurate enough for tracking progress |
| Bioelectrical impedance (scale) | ±4–8% | $30–300 | Convenient but highly variable with hydration status |
| BMI estimate | ±5–10% | Free | Very rough estimate; inaccurate for muscular individuals |
How to reduce body fat
The most effective strategy for reducing body fat combines a moderate calorie deficit with resistance training. Cardio accelerates fat loss but isn't strictly necessary — total calorie deficit is what drives fat loss regardless of method.
- ·Calorie deficit of 300–500 cal/day — enough to lose fat without sacrificing muscle
- ·High protein intake (0.7–1g per pound of bodyweight) — the most important factor for preserving lean mass during a cut
- ·Resistance training 3–4 days/week — maintains or builds muscle while fat is lost, improving body composition more than the scale shows
- ·Sleep 7–9 hours — sleep deprivation increases cortisol and hunger hormones, making fat loss significantly harder
- ·Track trends, not daily fluctuations — body fat percentage changes slowly; expect 0.5–1% improvement per month on a good program