Body Fat Calculator
Enter your height, neck and waist (and hips for women). The calculator works out an estimate of body fat and shows the usual bands.
This is an estimate for general information and is not medical advice. A tape measure cannot match a scan, so use it to follow your own change over time.
Worked examples
Man, 180 cm
Height 180 cm, neck 38 cm, waist 90 cm
About 19.8% body fat (Average band)
Metric Navy equation.
Woman, 165 cm
Height 165 cm, neck 32 cm, waist 80 cm, hips 100 cm
About 32.4% body fat
Uses the waist plus hips minus neck form.
About Body Fat Calculator
A body fat calculator estimates how much of your weight is fat, using only a tape measure. This one uses the US Navy circumference method, first published by Hodgdon and Beckett in 1984 for fitness screening in the armed forces. Men enter height, neck and waist, and women add their hips. The result is a percentage, plus the usual bands for your sex so you can see where you sit.
Scales and scans give better accuracy, but they are costly and not always to hand. A tape measure gets you a figure that is typically within three to four percentage points, which is good enough to follow your own progress. If you add your weight, the page also splits it into fat mass and lean mass. This is an estimate and not medical advice.
How to use Body Fat Calculator
- Choose metric or imperial units and your sex.
- Measure your neck below the larynx, your waist level with the navel and, for women, your hips at the widest point.
- Type the measurements and your height. Add your weight if you would like fat mass and lean mass.
- Read your body fat percentage and the band it falls in.
Common uses
- Tracking change during a training or diet plan
- Checking progress between gym assessments
- Working out fat mass and lean mass from a single weight
- Getting a body fat figure for the lean body mass or BMR calculators
Frequently asked questions
How accurate is the US Navy body fat method?
Studies find it is usually within about three to four percentage points of more detailed methods such as scans. It is less reliable for very muscular or very lean people. It is best used to follow your own change over time, measured the same way each time.
Where exactly should I measure?
Measure the neck just below the larynx (Adam’s apple), sloping slightly down to the front. Measure the waist level with the navel for men and at the narrowest point for women. Measure the hips at the widest point. Keep the tape snug, not tight.
What is a healthy body fat percentage?
The American Council on Exercise lists about 14 to 24% for men and 21 to 31% for women as the fitness to average ranges. Essential fat, below which the body struggles, is about 2 to 5% for men and 10 to 13% for women. Ranges are a guide and your GP can advise on your own situation.
Why does the calculator ask me to change the waist or neck?
For men the waist has to be larger than the neck, and for women the waist plus hips has to be larger than the neck. If the numbers do not fit, one is probably mistyped or measured in the wrong units, so check them.
Is this the same as BMI?
No. BMI only uses height and weight, so it cannot tell fat from muscle. A body fat estimate looks at where weight is carried. Neither is medical advice or a diagnosis, and both are best read alongside your GP’s view.