Body Fat Calculator for Women
Enter your height and three tape measurements (neck, waist and hip) to estimate your body fat percentage with the US Navy circumference method for women. Add your weight if you also want fat mass and lean mass.
Free, no sign-up. What you enter stays in your browser: it is not saved or sent to HerFound. Reviewed .
Units
Just below the larynx (voice box).
At the narrowest point.
At the widest point.
Only used for fat and lean mass.
Enter your height, neck, waist and hip measurements to see your estimated body fat percentage.
This is general information, not medical advice. It cannot take your own health history into account. For anything that worries you, speak to a doctor, midwife or pharmacist.
How it works
The calculator uses the US Navy circumference equation for women, developed by Hodgdon and Beckett at the Naval Health Research Center in 1984. With all measurements in inches: body fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387.
The published constants are for inches. If you enter centimetres, the calculator divides each measurement by 2.54 first, then uses the same equation.
Measure with a soft tape, flat against the skin and not pulled tight. Neck: just below the larynx (voice box). Waist: at the narrowest point of your middle. Hip: at the widest point around your bottom. Taking each measurement twice and using the average helps.
If you enter your weight, fat mass is weight × body fat % ÷ 100, and lean mass is the rest. Lean mass includes muscle, bone, organs and water.
What it cannot tell you
- It is an estimate from a tape measure. Compared with a DEXA scan, results for one person can be several percentage points too high or too low, and small changes in where you place the tape move the number.
- It is not valid in pregnancy, and it was developed with adult military personnel, so it may fit other groups less well. It is for adults only.
- The equation only knows four measurements. It cannot see where fat is carried or how much muscle you have, and it says nothing on its own about your health.
- If the result looks wrong, measure again before reading anything into it. A doctor can advise if you have questions about your body composition or health.
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Common questions
The US Navy body fat formula for women estimates body fat from height and three circumferences: neck, waist and hip. In inches, it is 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. A larger waist and hip relative to height and neck gives a higher estimate.
The Navy body fat calculator is a rough estimate that can be several percentage points away from a DEXA scan. A 2022 study of US Marines found that a circumference method of this kind read about 1 to 2 points higher than DEXA for women on average, and individual results commonly differed by 4 to 5 points either way. It is more useful for following a trend with the same tape and method than as an exact number.
For the women's Navy method, measure your waist at the narrowest point of your middle and your hips at the widest point around your bottom. Measure your neck just below the larynx. Keep the tape level and snug but not tight, and stand relaxed.
The body fat formula is different because women and men tend to carry fat in different places. The women's equation adds a hip measurement, and the men's equation uses the abdomen at the navel instead of the natural waist. Women also have a higher share of essential body fat than men.
Lean body mass is your body weight minus your fat mass. It includes muscle, bone, organs and water. This calculator estimates it as weight × (100 − body fat %) ÷ 100, so it is only as accurate as the body fat estimate.