Uses the US Navy circumference method. Tape measure required. Results are estimates — not medical advice.
ℹ️ About this calculator
Uses the US Navy circumference method — no weight needed. It measures body shape to estimate fat percentage, which is more useful than BMI. Accuracy: ±3–4% compared to a DEXA scan. Good for tracking changes over time.
Male
Female
The Navy formula uses waist, neck and height — plus hips for women. Keep the tape snug but not tight, and stand relaxed.
Height
cm
ft / in
Feet
Inches
Waist
Around belly-button level — the narrowest part of your middle
This Body Fat Calculator uses the US Navy circumference method to estimate your body fat percentage from a few tape-measure readings — no scales or weight needed. It is a more useful picture of body composition than BMI, and it is great for tracking changes as you train. Results are an estimate, not medical advice.
Typical body fat ranges for men and women (American Council on Exercise guide).
Category
Men
Women
Essential fat
2–5%
10–13%
Athletes
6–13%
14–20%
Fitness
14–17%
21–24%
Average
18–24%
25–31%
Above average
25%+
32%+
Ranges are general guidance and vary with age and genetics.
How the Navy method works
1
It measures shape, not weight — the formula uses the circumference of your waist and neck (and hips for women) against your height.
2
Men and women differ — women add the hip measurement because fat is distributed differently.
3
It estimates fat percentage — accurate to within about 3–4% of a DEXA scan for most people.
How to use it
1
Pick your sex and enter your height
2
Measure and enter your waist and neck (and hips if female)
3
See your body fat % and category update instantly, then copy the result
Frequently asked questions
It is a formula that estimates body fat from body measurements — height, neck and waist for men, plus hips for women — instead of weight. It was developed by the US Navy as a quick, equipment-light way to assess body composition.
The Navy method is usually within about 3–4% of a DEXA scan, which is the gold standard. It is far more useful than BMI for body composition, but it is still an estimate, so treat it as a guide and track changes over time.
Use a flexible tape, keep it level and snug without squeezing. Measure your waist at belly-button level, your neck just below the Adam’s apple, and (for women) your hips at the widest point. Measure on bare skin for the best result.
As a rough guide, many men sit in a healthy range around 10–20% and many women around 18–28%. Athletes are usually lower. Some fat is essential — about 2–5% for men and 10–13% for women.
For body composition, yes. BMI only uses height and weight, so a muscular person can be labelled overweight. Body fat percentage estimates how much of you is actually fat, which is more meaningful.
Men and women store fat differently, so the formula adds the hip measurement for women to account for that. Using the right version for your sex gives a more accurate estimate.
No. The Navy method only needs body measurements, so you can estimate your body fat with nothing but a tape measure.
Essential fat is the minimum your body needs to function — around 2–5% for men and 10–13% for women. Dropping below it is unhealthy and hard to sustain.
Yes, it is completely free, works on any device and needs no sign-up. Your measurements stay in your browser.