Body Fat % Calculator

Instructions

This calculator uses the US Navy method to estimate body fat percentage based on body circumference measurements. To take the measurements, you'll need a cloth measuring tape or some rope or string and a ruler. When taking measurements, pull tight enough so that the measuring tape isn't loose, but not so tight as to indent the skin. All measurements, other than hip, are meant to be taken on bare skin. For all measurements, keep the tape as level as possible and record to the nearest cm or half inch.

For males:

• Neck: look straight ahead with shoulders down and relaxed. Measure with the tape below the Adam's apple. Average is 15 in or 38 cm.
• Waist: stand up straight with good posture and arms at your sides. Do not suck in, just relax and breathe normally. Measure around the abdomen at the navel.

For females:

• Neck: look straight ahead with shoulders down and relaxed. Measure with the tape below the larynx. Average is 13.5 in or 34.5 cm.
• Waist: stand up straight with good posture and arms at your sides. Do not suck in, just relax and breathe normally. Measure at the point of smallest abdominal cirumference, usually about halfway between the navel and breastbone.
• Hip: measure around the greatest protrusion of gluteal muscles as viewed from the side. The tape can be pulled slightly tighter to minimize the effect of clothes.

How does this calculator work?

This calculator uses the US Navy formula to estimate body fat % based on body circumference measurements. It also creates a personalized scale of ranges based on your sex and age. The ranges are largely based on those used by the American Council on Exercise with some modifications to make them more understandable. Your rank is determined based on where your estimated body fat % places on your personalized scale.

How accurate is the estimation?

The US Navy method is accurate within about 3% if measurements are taken correctly. In comparison to more accurate methods, it's not that much less accurate and is significantly cheaper, simpler, and more convenient. A comparable, if slightly more complicated method, is using skinfold calipers.

How is this useful?

Your body fat % is a strong indicator of overall health and physical fitness. Being overfat or underfat carries significant health risks and can hinder physical performance. In addition, your body fat % directly affects your physical appearance. For all these reasons, knowing and tracking your body fat % is important and can help with tracking your progress.

For a complete body composition breakdown, your body fat percentage can be used to get your Body Composition Score.