Body Fat Calculator
Body fat percentage shows what proportion of your body weight consists of fat mass. It gives a more useful picture than BMI when assessing shape, health, and planning weight loss or muscle building.
Calculate Your Body Fat %US Navy Method
cm
kg
Measure at the navel
cm
Measure below the Adam's apple
cm
Why body fat is more useful than BMI
BMI only tells you the ratio between your weight and height. It does not distinguish between muscle and fat — which is the only thing that actually matters for health and body composition.
Same BMI — completely different body composition
A well-trained person weighing 75 kg at 175 cm (BMI 24.5) may have 12% body fat. An inactive person with the same measurements may have 28%. BMI looks identical — the body is fundamentally different.
Body fat percentage determines your actual calorie target
Lean body mass (LBM) is the strongest predictor of BMR. The more muscle mass you have, the higher your calorie needs. Two people with the same weight and activity level can have 200–300 kcal difference in TDEE solely due to differences in LBM.
The bridge to FFMI and muscle building
FFMI (Fat Free Mass Index) measures muscle mass relative to height and is the best measure for those who train. It is calculated directly from your body fat percentage and weight — and gives a much more precise goal to work toward than an ideal weight number.
How to measure correctly (US Navy Method)
- Waist measureme: * Measure horizontally at the navel — not at the narrowest point. Keep the tape snug but without pressing into the skin.
- Neck measureme: * Measure just below the Adam's apple. Keep the tape flat around the neck.
- Hip measurement (wome: * Measure at the widest point of the hips.
- Always measure in the morning, fasting, and on the same day each week for comparable results.
Frequently Asked Questions
How accurate is a body fat calculator?
The US Navy method has a typical margin of error of ±3–4 percentage points compared to DEXA scanning (the gold standard). It's accurate enough to track trends over time but doesn't give an exact value. Always measure in the same way and at the same time of day to compare results — relative change is more informative than absolute value.
Is body fat a better measure than BMI?
Yes, for most purposes. BMI only tells you about the weight-to-height relationship. Body fat tells you what proportion of your body is actually fat — which is what's health-relevant. Two people with the same BMI can have 15% and 30% body fat respectively. For fitness purposes, body fat is almost always more informative.
What is a good body fat percentage?
It depends on gender and goal. For men: athletic (6–13%), fit (14–17%), average (18–24%). For women: athletic (14–20%), fit (21–24%), average (25–31%). These are benchmarks — not medical thresholds. The most important thing is that your body fat doesn't increase uncontrollably and that you can sustain your level long-term.
Can you see abs at the same body fat percentage?
Yes. How visible abs are depends on muscle mass, fat distribution and genetics — not just body fat percentage. A person with 12% body fat but little muscle mass may have invisible abs, while a person with 14% and more muscle mass may have visible ones. That's why FFMI (Fat Free Mass Index) complements body fat well as a measure.
How quickly can you lower body fat?
A realistic reduction is 0.5–1% body fat per week with a well-planned calorie deficit of 400–600 kcal/day. Faster is possible but increases the risk of muscle loss. High protein intake (1.8–2.4 g/kg) and strength training are essential to preserve muscle mass during a cut.
Set a calorie goal that matches your body
Now you know your body fat. Calculate TDEE and start logging against a goal that actually fits.