Our body fat calculator uses the U.S. Navy circumference method — one of the most accurate ways to estimate body fat without expensive equipment. Simply enter your height, waist, neck (and hip for women) measurements to get your body fat percentage, lean body mass, and fat mass. We also show body fat categories and healthy ranges for your age and gender.
Measure at belly button level, relaxed
Narrowest point below Adam's apple
Widest point of hips/buttocks
Navy Method
Uses U.S. Navy formula, accurate within 3-4% of DEXA scans. Measure in the morning for consistency.
Body Fat Analysis (30yo Male, 80kg):
For men, 14-17% is "Athletic", 18-24% is "Fitness", 25%+ is "Average". Navy method is accurate within 3-4% of DEXA scans.
Select gender and enter your age, weight, and height accurately.
Measure at navel level (not narrowest point). Stand relaxed, don't suck in stomach.
Measure at the narrowest point, just below your Adam's apple.
Measure at the widest point of your hips/buttocks for accurate results.
The Navy body fat formula uses circumference measurements to estimate body fat. For men, it uses waist and neck measurements. For women, it also includes hip measurement. This formula has been validated against hydrostatic weighing and is accurate to within 3-4%.
Body Fat % = 495 / (1.0324 - 0.19077×log10(waist-neck) + 0.15456×log10(height)) - 450
Measure in the morning before eating for most consistent results
Use a flexible tape measure and don't pull too tight
Measure waist at navel level (not at the narrowest point)
Measure neck at the narrowest point below the Adam's apple
For women, measure hips at the widest point
Body fat varies throughout the day — measure at the same time for tracking
The Navy method is accurate to within 3-4% of DEXA scans
Our free body fat calculator uses the accurate U.S. Navy method to estimate your body fat percentage from simple measurements. No expensive equipment needed — just measure your waist, neck (and hip for women) to get your body fat %, lean body mass, fat mass, and see how you compare to healthy ranges.
The most accurate home method is the Navy formula using circumference measurements. For men, measure height, waist (at navel), and neck. For women, also measure hip at widest point. Our calculator applies the Navy formula to estimate body fat percentage accurate to within 3-4% of lab methods.
The Navy method using actual body measurements is more accurate than BMI-based estimates. BMI can't distinguish muscle from fat — a muscular person and overweight person may have the same BMI but very different body fat. Our calculator shows both methods for comparison.
Body fat categories differ by gender. For men: Essential (2-5%), Athletes (6-13%), Fitness (14-17%), Average (18-24%), Obese (25%+). For women: Essential (10-13%), Athletes (14-20%), Fitness (21-24%), Average (25-31%), Obese (32%+). Our calculator shows your category.
Besides body fat percentage, we calculate your lean body mass (muscle, bones, organs) and fat mass. Knowing these helps you track fitness progress — you want to lose fat while preserving or building lean mass. Lean body mass also determines your calorie needs.
Data sourced from trusted institutions
All formulas verified against official standards.