Body Fat Calculator
Estimate body fat percentage using the U.S. Navy tape-measure method.
Unlike BMI, which only uses height and weight, this estimates body fat percentage directly from circumference measurements using the U.S. Navy method — giving a more direct read on body composition.
How the Navy method works
This method uses your neck and waist measurements (plus hip measurement for women) in a logarithmic formula validated against more precise lab measurement techniques like hydrostatic weighing. It's not as accurate as a DEXA scan, but it's far more accessible and reasonably reliable for tracking trends over time.
Getting an accurate measurement
Measure your waist at your navel level, standing relaxed (not sucked in), and your neck just below the larynx. Small measurement errors compound in the formula, so measuring at the same time of day, in the same way, gives more consistent tracking than obsessing over a single reading's precision.
Frequently asked questions
Is this as accurate as a DEXA scan or body fat caliper test?
No — those methods are more precise, but circumference-based estimates like this one are reasonably good for tracking relative change over time, even if the absolute number has some margin of error compared to clinical methods.
What's a healthy body fat percentage range?
Healthy ranges differ by sex and age — commonly cited ranges are roughly 10-20% for men and 18-28% for women, though athletes often sit below these ranges. Consult a healthcare provider for guidance specific to your situation.