Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy tape-measure method. Get your fat category, lean mass, and fat mass breakdown instantly with no special equipment needed.
Measure just below the larynx, sloping downward to the front.
Enter your measurements
Fill in your height, neck, and waist circumference (plus hips for women) to calculate your body fat percentage using the U.S. Navy method.
U.S. Navy Method: This calculator uses the circumference-based formula developed by Hodgdon & Beckett (1984) for the U.S. Navy. It estimates body fat percentage from height, neck, waist (and hip for women) measurements. Results are estimates — DEXA, hydrostatic weighing, or air-displacement plethysmography provide higher accuracy.
What is the Body Fat Calculator?
The Body Fat Calculator estimates body fat percentage using the U.S. Navy circumference method — a tape-measure formula validated against DEXA scans that requires no special equipment. It uses neck, waist and (for women) hip measurements alongside height.
It's a reasonable estimate for tracking trends over time, not a precise clinical measurement.
How to use the Body Fat Calculator
- 1Choose your unit system: metric (cm) or imperial (inches).
- 2Enter your height, neck circumference and waist circumference. Women also enter hip circumference.
- 3Read your estimated body fat percentage and category.
- 4Measure at the same time of day and in the same way each time for consistent tracking.
Key features
- U.S. Navy circumference method
- Separate formulas for men and women
- Metric and imperial input
- Category ranges (essential, athletic, fitness, average, obese)
Important notes
- Measurement technique matters a lot here — a loose or overly tight tape can shift the result by several percentage points. Measure at the same tension each time.
- This method is less accurate for people at the extremes of height or body composition than DEXA or hydrostatic weighing.
- This is a fitness-tracking estimate, not a medical diagnostic tool.
Frequently asked questions
How accurate is the Navy method?
Studies generally show it within about 3–4 percentage points of DEXA scan results for most adults — accurate enough to track trends, not precise enough for clinical decisions.
Where exactly do I measure my waist?
At the narrowest point for men (typically at or just above the navel), and at the widest point for women — measure without pulling the tape tight.
Why do women need a hip measurement too?
The formula was derived separately for each sex because fat distribution patterns differ; the women's version adds hip circumference to improve accuracy.
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