Track trends
Use the percentage as a trend over time instead of a single fixed truth.
Enter your measurements
Measure consistently and keep units aligned for each field.
Gender
cm
Use the same tape placement each time so the trend stays consistent.
Use the result
How to use your body fat result
Use with other metrics
Combine with BMI, weight, and measurements for better context.
Method
Navy method, result meaning, and common mistakes
This free body fat calculator uses the U.S. Navy measurement method with height, neck, waist, and hip for female users where required.
How to use it
Measure at the same locations each time and compare the trend with BMI, calories, TDEE, and body measurements.
Common mistakes
Do not pull the tape too tight, switch measurement locations, or treat one estimate as a lab-grade body composition test.
Understand deeper
How the body fat percentage calculator estimates composition
This body fat percentage calculator uses the well-known Navy method body fat formula, a field method designed to estimate body composition from simple tape measurements rather than expensive lab equipment. Instead of relying only on scale weight, it uses height with neck and waist measurements for men, plus hip measurements for women, to estimate relative fatness. That makes it useful when comparing body fat vs BMI, because BMI cannot tell the difference between fat mass and lean mass. For people asking how to measure body fat at home, the biggest key is consistency: measure the same landmarks, stand naturally, and avoid pulling the tape too tight. The result is still an estimate, but it is practical for trend tracking and coaching decisions. Research from Hodgdon and Beckett at the Naval Health Research Center helped establish this method, and later population data has also informed discussion around healthy body fat percentage by age, ideal body fat for men and women, and the limits of visible-abs targets. Used correctly, the calculator gives better context than body weight alone.
The formula
Men: 495 ÷ (1.0324 - 0.19077 × log10(waist - neck) + 0.15456 × log10(height)) - 450.
Worked example
Male with waist 85 cm, neck 38 cm, and height 180 cm converts to about 33.5 in, 15.0 in, and 70.9 in, which gives an estimate near 17.5% body fat.
Scientific basis
Hodgdon & Beckett, Naval Health Research Center (1984), described the circumference-based equations that underpin the U.S. Navy body fat method.
Related calculators
Build more context
FAQ