Body fat uses the U.S. Navy circumference method (typically within ±3–4% of DEXA). The preview slider and 3D shape are illustrative, not medical advice.
Set a target
Pick a body fat goal and how long you want to take. See your target body and the daily calories to get there.
%
Now18.0%FitnessTarget12.0%Athlete
wks
Activity level
Target weight
74.6 kg−5.4 kg
Weekly change
−0.5 kg/week
Maintenance
2,460 kcal/day
Daily deficit
500 kcal/day
Eat about
1,960 kcal/day
Estimates assume you keep your lean mass and that 1 kg of fat is about 7,700 kcal. Maintenance uses the Katch–McArdle formula. Real needs vary, so adjust after a few weeks of weigh-ins.
Only body fat percentages are shown, never your measurements.
How the body fat calculator works
This calculator uses the U.S. Navy circumference method, which estimates body fat percentage from your height and a few tape measurements: neck and waist for men, plus hips for women. It is typically within 3–4 percentage points of a DEXA scan, and all you need is a tape measure.
As you type, ShapeTwin builds a 3D twin of your body from your measurements, so you can see how your shape relates to your body fat level. In Advanced mode you can add chest, arm, thigh and calf measurements to refine your twin, and preview how you might look at a different body fat percentage.
How to measure yourself
Use a flexible tape measure, snug against the skin without compressing it.
Neck: just below the larynx (Adam's apple), with the tape sloping slightly down to the front.
Waist: men at the navel, women at the narrowest point. Stand relaxed and don't pull your stomach in.
Hips (women): around the widest part of the buttocks.
Measure at the same time of day, ideally in the morning, and average two or three readings.
Body fat ranges
The American Council on Exercise groups body fat percentages into these ranges:
Category
Men
Women
Essential
2–5%
10–13%
Athlete
6–13%
14–20%
Fitness
14–17%
21–24%
Average
18–24%
25–31%
Obese
25%+
32%+
Frequently asked questions
How accurate is the U.S. Navy method?
For most people it lands within about 3–4 percentage points of a DEXA scan. Accuracy depends mostly on measuring consistently, so use the same tape, spot and time of day each time.
Is my data stored?
No. All calculations run in your browser, and nothing you enter is sent anywhere unless you sign in and choose to save a measurement.
What is a healthy body fat percentage?
For general health, roughly 10–20% for men and 20–30% for women is considered healthy. Very low levels are not sustainable for most people. Ask a doctor for personal advice.
Why is the result different from my smart scale?
Smart scales estimate body fat with bioelectrical impedance, which shifts with hydration and time of day. Tape measurements are usually more consistent, so track trends over time with one method.