Body Fat Calculator
Estimate your body fat percentage using the US Navy Method — one of the most accurate measurement-based formulas available. Enter your measurements for an instant result with category rating, body composition breakdown and personalised advice.
How to Take Accurate Measurements
The accuracy of the US Navy Method depends entirely on taking consistent measurements. Use a soft measuring tape and measure at the same time each day — ideally first thing in the morning.
How Is Body Fat Percentage Calculated?
This calculator uses the US Navy Method developed by Hodgdon and Beckett at the Naval Health Research Center in 1984. It uses circumference measurements and a logarithmic formula to estimate body fat percentage without specialist equipment.
Body Fat Percentage Categories
Body fat categories differ between men and women because women naturally carry more essential fat due to hormonal and reproductive differences.
| Category | Men | Women | What It Means |
|---|---|---|---|
| Essential Fat | 2–5% | 10–13% | Minimum fat for basic bodily function |
| Athlete | 6–13% | 14–20% | Competitive athlete level — very lean |
| Fitness | 14–17% | 21–24% | Lean, fit and healthy |
| Average | 18–24% | 25–31% | Typical healthy adult range |
| Obese | 25%+ | 32%+ | Excess body fat — health risks increase |
Body Fat vs BMI — What's the Difference?
BMI uses only height and weight and cannot distinguish between fat and muscle. A muscular person can have a high BMI despite low body fat. Body fat percentage is a more accurate indicator of body composition and health risk.
| Metric | What It Measures | Limitation |
|---|---|---|
| BMI | Weight relative to height | Can't distinguish fat from muscle |
| Body Fat % | Proportion of body that is fat | Doesn't account for fat distribution |
| Waist circumference | Abdominal fat specifically | Doesn't measure overall fat percentage |
| DEXA scan | Precise fat, muscle and bone density | Requires specialist equipment |
Use body fat percentage alongside BMI and waist circumference for the fullest picture of your body composition and health risk.
How to Reduce Body Fat Percentage
Reducing body fat requires a calorie deficit — consistently consuming fewer calories than you burn. The most effective approach combines dietary changes with resistance training to preserve muscle mass while losing fat.
- Create a moderate calorie deficit — 300–500 calories per day leads to 0.3–0.5kg of fat loss per week without excessive muscle loss
- Prioritise protein — 1.6–2.2g per kg of bodyweight preserves lean muscle during a calorie deficit
- Include resistance training — lifting weights maintains muscle mass and keeps your metabolic rate higher during fat loss
- Be patient with the rate — losing 0.5–1% of bodyweight per week is sustainable and protective of muscle
- Recalculate regularly — as you lose weight your TDEE decreases, so calorie targets need adjusting every 4–6 weeks
FAQs
How accurate is the US Navy Method?
The US Navy Method has an accuracy of approximately ±3-4% compared to gold standard methods like DEXA scanning. It’s one of the most accurate measurement based methods available without specialist equipment.
What is a healthy body fat percentage?
For men 14-17% is considered fitness level and 18-24% is average healthy. For women 21-24% is fitness level and 25-31% is average healthy. These ranges vary by age — older adults naturally carry slightly more body fat.
How is body fat different from BMI?
BMI uses height and weight only and cannot distinguish fat from muscle. Body fat percentage directly measures how much of your body is fat making it a more useful health marker especially for active or muscular individuals.
How can I reduce body fat percentage?
A calorie deficit combined with resistance training is the most effective approach. The deficit burns fat while resistance training preserves and builds muscle — improving body composition even when total weight loss is modest.
What is essential body fat?
Essential fat is the minimum fat required for basic physiological functions — protecting organs, regulating hormones and supporting the nervous system. For men this is 2-5% and for women 10-13%. Going below essential fat levels is dangerous.
Is this calculator free?
Yes completely free with no sign-up needed.