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 simple tape-measure circumferences and height to estimate body fat percentage. It was published by Hodgdon and Beckett in 1984 and validated against hydrostatic weighing, which is why it remains a popular free at-home estimate. The formulas use logarithms to account for the way fat distributes around the trunk, neck, and hips, and they differ by sex.
| 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 lower your body fat percentage
Body fat percentage falls when fat mass drops faster than lean mass — so the aim of a good plan is to shed fat while holding onto muscle, not just to make the scale go down. A modest, sustainable energy deficit paired with strength work and enough protein does exactly that.
- ·Eat in a moderate deficit of roughly 300–500 calories a day — aggressive crash dieting strips muscle along with fat
- ·Keep protein high (about 0.7–1g per pound of bodyweight) to protect lean tissue while you are in a deficit
- ·Lift weights 3–4 times a week so the body has a reason to keep the muscle it has
- ·Protect sleep — short sleep raises hunger hormones and cortisol and quietly stalls fat loss
- ·Judge progress by the monthly trend, not single readings; a drop of about 0.5–1 percentage point per month is solid, realistic progress