Body Fat Calculator
Estimate body fat % (U.S. Navy method)
Estimate your body fat percentage with the U.S. Navy tape method — just a few measurements and no special equipment.
How to measure
Measure your neck and waist (at the navel), plus hips for women, with a flexible tape — relaxed, not sucking in. Accuracy depends on consistent measurements.
An estimate, not a clinical measurement (like a DEXA scan).
Getting consistent numbers
Measure at the same time of day (mornings are best), keep the tape level and snug without compressing the skin, and take each measurement twice and average it. Because the method relies on circumferences, small differences in tape placement change the result — consistency matters more than perfection.
Reading the result
The Navy formula estimates body fat from the ratio of waist to neck (and hips for women), so it captures the health-relevant fact that belly fat carries more risk. It's best used to track change over time — a steady downward trend as you train and eat well means more than the exact percentage on any single day.
Body Fat Calculator: frequently asked questions
What's a healthy body fat percentage?
Roughly 10–20% for men and 18–28% for women is typical for healthy adults, varying with age and fitness.
How accurate is the Navy method?
Within a few percent for most people when measured carefully — good for tracking trends over time.
What's the difference between BMI and body fat percentage?
BMI uses only height and weight and can't tell muscle from fat. Body fat percentage estimates how much of your weight is actually fat, so it's a better gauge of fitness — two people with the same BMI can differ a lot.