Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Body Fat Calculator (Navy Method)

Estimates body fat percentage using the U.S. Navy circumference method, which needs only a tape measure — no calipers or scales. It combines neck, waist, height (and hip for women) into a validated equation used by the military for body-composition screening.

Sex

Height (cm)

Neck Circumference (cm)

Waist Circumference (cm)

Hip Circumference (women) (cm)

Fitness

BMI Calculator

Calculate Body Mass Index (BMI) — body weight in kg divided by height in metres squared — to screen for under/overweight categories. The most widely used population-level fitness and health risk metric, with known limitations for athletes and unusual body compositions.

Weight (kg)

Height (cm)

Key differences

	Body Fat Calculator (Navy Method)	BMI Calculator
Category	Health	Fitness
Inputs required	5	2
Result	Estimated Body Fat (%)	Your BMI
What it does	Estimates body fat percentage using the U.S. Navy circumference method, which needs only a tape measure — no calipers or scales. It combines neck, waist, height (and hip for women) into a validated equation used by the military for body-composition screening.	Calculate Body Mass Index (BMI) — body weight in kg divided by height in metres squared — to screen for under/overweight categories. The most widely used population-level fitness and health risk metric, with known limitations for athletes and unusual body compositions.