Body fat calculator
Estimate body fat percentage from height and circumference measurements using the U.S. Navy formula. The result is a rough estimate.
Estimate body fat percentage
Choose the U.S. Navy formula you want to use. The male formula uses height, waist and neck measurements. The female formula also uses hip measurement.
What the body fat calculator shows
The calculator estimates what share of body weight is body fat from height and selected circumference measurements. The male formula uses height, waist and neck. The female formula also uses hip measurement.
How to use the calculator
- Choose the male or female U.S. Navy formula.
- Enter height in centimeters.
- Enter neck and waist circumference in centimeters.
- For the female formula, also enter hip circumference.
- You can use either a comma or a dot in decimal numbers. The calculator converts centimeters to inches.
Method and calculation logic
The calculator uses the U.S. Navy circumference formulas. The formulas are logarithmic, so consistent measurement technique matters.
- Male formula: 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76.
- Female formula: 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387.
All measurements are converted from centimeters to inches before the formula is applied.
Examples
- With the male formula, height 180 cm, waist 85 cm and neck 38 cm gives about 16.2%.
- With the female formula, height 165 cm, waist 75 cm, neck 32 cm and hips 95 cm gives about 27.7%.
What the result means
The result is a mathematical estimate of body fat percentage for the measurements you entered. It can be used as a rough comparison value over time if you measure consistently. The calculator does not show body fat categories and does not assess overall health.
Limitations
The body fat calculator is not an exact body composition measurement. Small changes in waist, neck or hip measurement can change the estimate.
It does not replace DEXA, bioimpedance, skinfold measurement or a professional assessment. It does not provide a diagnosis, medical advice or personalized health guidance.
Health disclaimer
The result is an estimate. It is not medical advice, not a diagnosis and not personalized health guidance. If you have concerns about weight, eating, health or body image, consider speaking with a healthcare professional.
FAQ
How is body fat percentage calculated here?
This calculator uses the U.S. Navy circumference formula with height, waist, neck and, for the female formula, hip measurement.
Is the result accurate?
No. The result is an estimate. Measurement location, tape tension and individual differences can affect the value.
Why does neck circumference matter?
In the U.S. Navy formula, neck circumference is part of a proportion-based estimate. It does not by itself measure body fat.
What is the difference between BMI and body fat percentage?
BMI describes weight in relation to height. Body fat percentage tries to estimate the fat mass share of body weight. Neither value alone gives a full picture of health.
When should I interpret the result cautiously?
Interpret it cautiously if measurements are uncertain, your body type differs from the formula assumptions or the result would influence health-related decisions.