Body Fat Calculator
Estimate your body fat using the US Navy method
Body Fat Ranges
Why Body Fat Percentage Matters More Than Weight
Two people can weigh the same and look completely different. A 180-pound person at 15% body fat carries 27 pounds of fat and 153 pounds of lean mass (muscle, bone, organs, water). A 180-pound person at 30% body fat carries 54 pounds of fat and 126 pounds of lean mass. Same weight, vastly different body composition, different health profiles, and different appearance. The scale cannot tell you which one you are — only body fat measurement can.
The US Navy method used in this calculator estimates body fat from circumference measurements. It is not as accurate as DEXA scans or hydrostatic weighing, but it is free, requires no equipment beyond a tape measure, and is accurate to within 3-4% for most people. For tracking changes over time — which is more useful than a single measurement — the Navy method is reliable because the margin of error is consistent. If it says you went from 22% to 19%, you genuinely lost about 3% body fat even if the absolute number is slightly off.
How to Take Accurate Measurements
Waist: measure at the navel, not at your pants' waistband (which sits lower). Stand relaxed — do not suck in your stomach. The tape should be snug but not compressing the skin. Neck: measure just below the Adam's apple (or the equivalent position on women), with the tape level around the neck. Hips (women only): measure at the widest point of the buttocks with feet together. Take each measurement twice and use the average. Measure at the same time of day (morning is best) for consistency.
How accurate is this method?
The US Navy method is accurate to within 3-4% for most people. It tends to underestimate body fat in very lean individuals and overestimate in very muscular individuals. For tracking changes over time, it is reliable and consistent. For a precise single measurement, a DEXA scan ($50-150 at most hospitals) is the gold standard.
What is a healthy body fat percentage?
For men: 14-24% is the healthy range, with 14-17% being the "fitness" category. For women: 21-31% is healthy, with 21-24% being "fitness." Below essential fat levels (2-5% men, 10-13% women) is dangerous. Competitive bodybuilders reach 3-5% briefly for competitions but do not maintain it — it is not sustainable or healthy long-term.