Body Fat Percentage Calculator
Estimate your body fat percentage using the US Navy tape-measure formula.
How to use
- Pick your units and gender, then enter your height, neck and waist (plus hip for women).
- Click Calculate.
- See your estimated body fat percentage and fitness category.
For information only — not medical advice. Consult a healthcare professional for personal guidance.
What Is a Body Fat Calculator?
Your body fat percentage is the share of your total weight made up of fat tissue — a far more informative number than weight or BMI alone. Two people can weigh exactly the same while one carries mostly muscle and the other mostly fat, with very different health profiles. This calculator estimates your body fat percentage from simple tape measurements — height, neck, waist, and (for women) hip — using the US Navy circumference method, so you can track real changes in composition rather than just changes on the scale.
The Navy method was developed for assessing thousands of service members quickly and cheaply, without laboratory equipment. It exploits a consistent relationship: fat is stored disproportionately at the waist, while the neck measurement helps correct for overall frame and muscle. Validated against reference methods, it typically lands within a few percentage points for most people.
How to Use the Body Fat Calculator
- Choose imperial (inches) or metric (cm) units.
- Select your gender — the formula differs for men and women.
- Measure and enter your height, your neck just below the larynx, and your waist at the navel. Women also enter hip circumference at its widest point.
- Click Calculate to see your estimated body fat percentage and category.
Reading Your Result
Commonly used categories (from the American Council on Exercise) for men: essential fat 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, obese 25% and above. For women: essential 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, obese 32% and above. Women carry more essential fat for hormonal and reproductive health, so the ranges are not interchangeable. Measure first thing in the morning, keep the tape snug but not compressing the skin, and repeat each measurement twice for consistency.
Tips for Tracking Body Fat
- Track the trend every two to four weeks under identical conditions — single readings wobble with hydration, meals, and tape placement.
- Combine the estimate with waist circumference and progress photos; together they tell a clearer story than any one number.
- Chase the category above yours rather than an extreme: moving from "average" to "fitness" delivers most of the health benefit with a fraction of the difficulty.
How accurate is the Navy method?
Compared with DEXA scans and hydrostatic weighing, the circumference method is generally accurate to within about 3–4 percentage points for most people. It is less reliable at the extremes of muscularity — very lean bodybuilders and people with unusual fat distribution can read misleadingly — but for tracking change over time it is more than sufficient.
Why does the calculator ask for neck size?
The neck measurement acts as a proxy for lean mass and frame size. Because necks carry relatively little fat compared with the waist, subtracting the neck from the waist isolates the fat-storage signal. That is also why the measurement must be taken just below the larynx, with the tape perpendicular to the neck.
What is a healthy body fat percentage?
It depends on age, gender, and goals. As a general guide, roughly 14–24% for men and 21–31% for women covers the fitness-to-average range associated with good metabolic health for most adults. Ranges drift slightly upward with age. Extremely low percentages are neither necessary nor healthy for most people.
Can I lose body fat without losing weight?
Yes — that is body recomposition: losing fat while gaining muscle keeps scale weight nearly constant while body fat percentage falls. It happens most readily in beginners, returning trainees, and people eating adequate protein while resistance training. This is exactly the situation where a body fat estimate reveals progress the scale hides.