How to use the Body Fat Calculator
Select your sex and preferred method, then enter the required measurements. The result updates instantly — no button needed.
Navy Method (recommended)
The US Navy Method uses body circumference measurements to estimate fat distribution. It is the most practical at-home method with a margin of error of approximately 3–4 percentage points.
- Height: Stand straight against a wall, without shoes.
- Neck: Measure just below the larynx (Adam's apple), tilting the tape slightly downward at the front.
- Waist (men): Measure at navel level, relaxed — not sucked in.
- Waist (women): Measure at the narrowest point, usually just above the navel.
- Hip (women only): Measure at the widest point of the hips and buttocks.
BMI-based method (Deurenberg)
The Deurenberg formula estimates body fat from weight, height and age. It is less accurate than the Navy Method because it does not account for individual body shape or fat distribution, but it requires no tape measure.
- Men: %BF = (1.20 × BMI) + (0.23 × age) − 16.2
- Women: %BF = (1.20 × BMI) + (0.23 × age) − 5.4
Frequently asked questions
What is a healthy body fat percentage?
According to the American Council on Exercise (ACE), the fitness range is 14–17% for men and 21–24% for women. The average range is 18–24% for men and 25–31% for women. Below 5% (men) or 13% (women) represents essential fat only, which is not sustainable.
How accurate is the Navy Method?
The US Navy Method has a typical error of 3–4 percentage points compared to DEXA scans. It is more accurate than BMI-based formulas and significantly more accessible than laboratory methods such as hydrostatic weighing or air displacement plethysmography.
What is the difference between the Navy Method and BMI-based formula?
The Navy Method uses circumference measurements to account for individual body shape and fat distribution. The BMI-based formula estimates body fat purely from weight, height and age — it is faster but less accurate, especially for athletes or people with unusual body proportions.
Can I reduce body fat without losing muscle?
Yes. A moderate calorie deficit of 300–500 kcal per day combined with resistance training is the most effective strategy for reducing body fat while preserving muscle mass. Adequate protein intake (1.6–2.2 g per kg of body weight) is also essential.