Body Fat Calculator — Army Method
Calculate body fat percentage with simple measurements (neck, waist, height) using the army formula.
Tip: Always measure at the same time of day (morning, empty stomach) for consistency — the waist can vary by 2-3 cm during the day.
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About this digital tool
The army-method body fat calculator (tape test) estimates fat percentage using only a tape measure. For men, enter height and neck and waist circumference; for women, hip circumference is added too. The result is given as a percentage together with the category.
The formula is the same as the US Department of Defense one and uses the logarithm of the difference between waist and neck (for women, waist plus hips minus neck) and of height. It is suitable for tracking change over the weeks, always measuring under the same conditions. It does not replace accurate methods such as DEXA and can over- or under-estimate in very muscular people or those with an unusual build. If you need a medical assessment, see a specialist.
How to use
- Enter your gender
- Enter your height (cm)
- Measure and enter the neck circumference (cm)
- Measure and enter the waist circumference (cm)
- Measure the hip circumference (women only)
- See the estimated body fat percentage
Frequently asked questions
How are the circumferences measured?
Waist: measure at navel level (men) or the narrowest point (women). Neck: measure below the Adam's apple. Hips (women only): measure at the widest point.
How accurate is this method?
Accuracy: ±3-4% compared with laboratory methods. For most people it gives a good estimate. It can be slightly off for very muscular people or those with an atypical fat distribution.
What are the normal values?
Men: 6-13% athletes, 14-17% fit, 18-24% average, 25%+ obese. Women: 14-20% athletes, 21-24% fit, 25-31% average, 32%+ obese.
How accurate is the army method?
It is an estimate with an error of a few percentage points. It works well for tracking change over time, but it is not a diagnosis.
Why does the result change if I measure at different times?
The waist changes during the day with food and water. Always measure at the same time, ideally in the morning on an empty stomach.