Estimate your body fat percentage using the U.S. Navy circumference method. More accurate than BMI for assessing body composition.
Last updated: March 2026
Medical disclaimer: This calculator provides an estimate only and is for informational and educational purposes only. It is not a medical device and is not a substitute for professional medical advice, diagnosis, or treatment.
The U.S. Navy method is an estimation tool and may have accuracy variations of ±3-4%. Individual body fat can vary based on genetics, fitness level, body composition, and measurement accuracy. Use results with caution and consult a qualified healthcare professional before making medical, training, or nutrition decisions.
Body fat percentage is the proportion of fat in your body compared to everything else (bones, muscles, organs, and water). Unlike BMI, which only uses height and weight, body fat percentage gives a more accurate picture of your body composition and overall health.
The U.S. Navy method is a widely-used formula that estimates body fat using circumference measurements of specific body parts. It was developed by the U.S. Navy to assess fitness levels of service members and has become popular due to its simplicity and reasonable accuracy without requiring expensive equipment.
For men, the formula uses height, neck, and waist measurements. For women, hip circumference is also included since women naturally carry more fat in the hip and thigh areas. This method typically has an accuracy within ±3-4% of more sophisticated methods like DEXA scans.
Height
Stand straight against a wall. Measure from floor to top of head.
Neck
Measure just below the larynx (Adam's apple). Keep tape level and snug but not tight.
Waist
For men: measure at navel level. For women: measure at narrowest point. Keep tape horizontal, don't pull tight.
Hip (Women only)
Measure at the widest part of the buttocks. Keep tape parallel to floor.
Men
Women
Calculate body fat for a male: Height 175cm, Neck 38cm, Waist 85cm:
The Navy method is typically accurate within ±3-4% when measurements are taken correctly. While not as precise as DEXA scans or hydrostatic weighing, it's a practical and free option that provides reasonably reliable results for most people.
For men, 10-20% is generally healthy, with athletes often at 6-13%. For women, 18-28% is healthy, with athletes at 14-20%. Women naturally have higher essential fat (10-13%) compared to men (2-5%) for reproductive functions.
Neck circumference correlates with lean body mass. People with more muscle tend to have thicker necks. This helps the formula distinguish between fat and muscle mass, making the estimate more accurate than using waist measurement alone.
Yes! For best results, measure at the same time of day (morning is best), use the same tape measure, and measure in the same spots each time. Track measurements weekly or monthly to see trends rather than daily fluctuations.
Generally yes, especially for athletes or muscular individuals. BMI doesn't distinguish between muscle and fat, while body fat percentage directly estimates fat mass. However, both are screening tools with limitations.
For men, measure at the navel (belly button) level. For women, measure at the natural waist (narrowest point between ribs and hips). Keep the tape snug but don't compress the skin. Breathe normally.
Women naturally store more fat in the hip and thigh region due to hormonal differences. Including hip measurement improves accuracy for women by accounting for this natural fat distribution pattern.
Yes! Going below essential fat levels (5% for men, 13% for women) can cause serious health problems including hormone disruption, weakened immune system, and organ damage. Essential fat is necessary for basic physiological functions.
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