Health & Fitness
Body Fat Calculator
Get your body fat percentage from the U.S. Navy tape method, see where it lands for your age, and find out how much fat you would need to lose to hit a target.
How it works
Behind the numbers
A scale tells you your weight, not what the weight is made of. This calculator uses the U.S. Navy method, a formula the military uses to estimate body fat from tape measurements instead of calipers or lab equipment. Men enter height, neck, and waist. Women add hips. The numbers run through a logarithmic formula and out comes a body fat percentage.
The number means more next to a reference. The page shows your ACE category (athletes, fitness, acceptable, obese) and the Jackson and Pollock ideal range for your age group. It also splits your weight into fat mass and lean mass, so you can tell what is actually changing when the scale moves.
The goal planner answers the practical question: how much fat do you need to lose to reach a target percentage. Set the target and it works backwards from your current lean mass. Measure every few weeks, same spots, same time of day. Everything runs in your browser. Nothing you type leaves the page.
FAQ
Questions, answered
How accurate is the Navy body fat calculator?
Within about 3 to 4 percentage points for most people. A DEXA scan is tighter, around 1 to 2 points, but the tape method beats guessing by a mile. The tape is the main source of error: measure in the same spots at the same time of day, and the trend matters more than any single reading.
Where exactly do I measure my neck, waist, and hips?
Neck: just below the Adam's apple, tape flat and snug. Waist: around the navel for men, at the narrowest point for women. Hips (women): the widest point. Keep the tape level, do not pull it tight, exhale normally and read before you breathe in again.
What is a healthy body fat percentage?
For men, 14 to 24 percent is the general fitness range; for women, 21 to 31 percent. Athletes run lower: 6 to 13 percent for men, 14 to 20 percent for women. These are the ACE categories used across the fitness industry. The ideal range also shifts upward with age, which the calculator shows for your age group.
Why does my BMI say overweight but my body fat looks fine?
BMI divides weight by height squared and cannot tell muscle from fat, so a muscular person lands in “overweight” with low body fat. That gap is exactly what this page fills: it shows the Navy estimate and a BMI-based estimate side by side so you can compare them on your own numbers.
How much fat do I need to lose to reach my goal?
Set your target percentage in the goal planner and it computes the fat mass to lose, assuming your lean mass stays put. A realistic pace is about half a percent of body fat per month through diet and training. Recheck with the tape every two to four weeks.