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Body Fat Percentage Calculator
Estimate your body fat percentage with the U.S. Navy circumference method, using neck, waist (and hip) measurements.
This tool provides a general estimate only and is not a substitute for professional medical advice; talk to a doctor about decisions affecting your personal health. The categories shown are not diagnostic.
What is the U.S. Navy method?
This method was developed in the 1980s for the U.S. Navy to estimate body fat percentage without calipers or expensive equipment. The calculator converts every measurement to inches and applies a logarithmic formula: for men it's based on waist minus neck; for women it uses waist plus hip minus neck, since fat distribution in women is typically spread across the hips and thighs as well as the abdomen.
The result is an estimate, not a lab measurement like DEXA or hydrostatic weighing; accuracy is typically within a few percentage points. It's more useful for tracking your own trend over time (say, monthly) than as a single precise number. The categories shown (essential, athletic, fit, average, high) are general reference ranges and should be treated as a rough guide only.
Frequently asked questions
What is the U.S. Navy method?
A body fat estimation method developed for the U.S. Navy that uses neck, waist (and, for women, hip) circumference measurements plus height, without calipers or scanning equipment.
How accurate is this estimate?
It's typically accurate to within a few percentage points compared with lab methods like DEXA, and works well for tracking your own trend over time.
Why does the female calculation need a hip measurement?
Body fat in women tends to be distributed around the hips and thighs as well as the abdomen, so the formula for women adds hip circumference to better reflect that.
What do the body fat categories mean?
They're general reference bands (essential, athletic, fit, average, high) used to describe typical ranges — they are not a medical diagnosis.