Your Measurements
Measurement Guide
Waist: Measure at the narrowest point (or navel) while exhaling normally. Keep the tape snug but not compressing skin.
Neck: Just below the larynx (Adam's apple). Tilt head slightly forward. Tape should slope downward slightly at front.
Enter measurements
Enter your measurements to see personalized results with health context.
Body Fat Percentage Ranges
Where you fall on the body fat spectrum, with color-coded zones for men and women.
Body Composition vs. Weight
Why body fat percentage is a better measure of fitness than the scale alone.
The Scale Lies
Two people at 180 lbs can have drastically different body compositions. One may be 15% body fat with significant muscle, while another is 30% body fat. The scale cannot distinguish between muscle, fat, water, and bone.
Health Risks by Body Fat
Excess visceral fat (around organs) is linked to heart disease, type 2 diabetes, and metabolic syndrome -- regardless of what the scale reads. Body fat percentage captures this risk far better than BMI.
Track Changes Over Time
When you strength train, you may gain muscle while losing fat. The scale may not move, but your body fat percentage drops. Measure monthly to track true progress -- not just weight fluctuations.
How the US Navy Body Fat Formula Works
The US Navy body fat estimation method uses circumference measurements -- waist, neck, height (and hip for women) -- to calculate body fat percentage. Developed for military fitness assessments, it provides accuracy within 3% of hydrostatic (underwater) weighing for most individuals.
Male Formula
Body Fat % = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450
Female Formula
Body Fat % = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450
When to Measure
For the most consistent results, take measurements first thing in the morning before eating or drinking. Use a flexible tape measure (not a spring-loaded one) and take each measurement three times, using the average. Measure at the same time of day each time you check.
Limitations
The Navy method may overestimate body fat in very muscular individuals and underestimate it in those with central obesity. For the most accurate assessment, consider DEXA scanning or hydrostatic weighing. However, for tracking changes over time, the Navy method is highly reliable and free.
Related Calculators
Continue exploring your fitness metrics with these tools.