Body fat for females aged 50 to 59
Enter your height and tape measurements to estimate body fat. The example is a woman in her 50s, 5 ft 4 in tall, with a 31 inch waist, a 38.5 inch hip and a 13.25 inch neck.
How it works
The female Navy formula adds waist and hip and subtracts neck, then takes the base 10 log of the result. Multiply by 163.205. Then subtract 97.684 times the base 10 log of height and subtract 78.387. For a woman in her 50s at 64 inches, waist plus hip minus neck is 56.25 inches.
Worked example
A woman in her 50s who is 5 ft 4 in tall has a 31 inch waist, a 38.5 inch hip and a 13.25 inch neck. Waist plus hip minus neck is 56.25 inches. The base 10 log of 56.25 is 1.75012, and 1.75012 × 163.205 = 285.628. The base 10 log of 64 is 1.80618, and 1.80618 × 97.684 = 176.435. 285.628 − 176.435 − 78.387 = 30.81, which rounds to 30.8 percent. That is in the average range.
Common questions
Why does the waist matter more than weight?
Waist size reflects fat carried around the middle, while body weight cannot tell fat from muscle. For a woman in her 50s, a waist of 31 inches against a height of 64 inches gives a waist-to-height ratio of 0.48.
Can I enter centimeters?
Yes. Switch the units and the page converts everything to inches before it does the math. For a woman in her 50s at 5 ft 4 in, a waist of 31 inches is 78.7 cm and a neck of 13.25 inches is 33.7 cm.
How accurate is the Navy method?
It is an estimate. It is usually within a few percentage points of more precise methods, and careful measuring matters. For a woman in her 50s at 5 ft 4 in, a reading of 30.8 percent could be a few points higher or lower in practice.
Where do I place the tape?
Measure the neck just below the larynx. For men measure the waist at the navel. For women measure the waist at its narrowest point and the hips at their widest. Keep the tape snug and level without squeezing. For a woman in her 50s at 5 ft 4 in the waist number is 31 inches and the neck number is 13.25 inches.
Does age change the result?
The formula does not use age. The same measurements give the same estimate at any age. A woman in her 50s at 5 ft 4 in with a 31 inch waist, a 38.5 inch hip and a 13.25 inch neck gets 30.8 percent.