Question 1

How is body fat percentage calculated?

Accepted Answer

This calculator uses the US Navy method, which requires circumference measurements of the neck, waist, and hip (for women). The formula uses logarithms and is validated against hydrostatic weighing.

Question 2

What is a healthy body fat percentage?

Accepted Answer

For men: 8–19% is generally healthy. For women: 21–33% is healthy. Athletes typically fall at the lower end. Above 25% (men) or 32% (women) is considered obese.

Question 3

What measurements do I need for the US Navy formula?

Accepted Answer

Men need: neck circumference and waist circumference (at navel). Women additionally need hip circumference (at widest point).

Question 4

How accurate is the US Navy body fat formula?

Accepted Answer

The Navy formula is accurate to within 3–4% for most people. It is a reliable field test compared to DEXA scan (gold standard). Accuracy decreases at very high or very low body fat levels.

Question 5

What is the difference between BMI and body fat percentage?

Accepted Answer

BMI is based solely on height and weight. Body fat percentage measures actual fat proportion. A muscular person can have high BMI but low body fat, making body fat percentage more informative.

Question 6

How do I reduce body fat?

Accepted Answer

Combine a moderate calorie deficit with resistance training (to preserve muscle) and cardiovascular exercise. Sustainable fat loss is 0.5–1% body fat per month.

Body Fat Calculator

US Navy Body Fat Formula