Body Fat Calculator
Estimate your body fat percentage from a few simple tape measurements.
This is a general estimate using a field-method formula, not a clinical body composition measurement. Consult a healthcare professional for precise assessment.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletic | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25%+ | 32%+ |
Frequently asked questions
How is body fat percentage estimated here?
This calculator uses the U.S. Navy circumference method, which estimates body fat from neck, waist (and for women, hip) measurements combined with height. It's a widely used field method, not a lab-grade measurement.
How accurate is this method?
The Navy method is reasonably accurate for most people as a general estimate, typically within a few percentage points of more precise methods like DEXA scans, but it can be less reliable for very lean or very muscular individuals.
Where exactly should I measure?
Measure your neck just below the larynx, your waist at the narrowest point (or at the navel), and for women, hips at the widest point. A soft measuring tape held snug but not tight gives the most consistent results.
What's a healthy body fat percentage?
Healthy ranges vary by sex, age, and fitness goals, generally somewhere around 10-20% for men and 18-28% for women, though a doctor or fitness professional can give a more personalized assessment.
What body fat percentage is considered athletic?
Using the ranges in this calculator, “Athletic” falls between about 6–13% for men and 14–20% for women. See the categories table above for the full breakdown.
Can body fat percentage be too low?
Yes — dropping below the “essential fat” range (roughly under 2–5% for men, under 10–13% for women) can impair hormone production and organ function. Essential fat is the minimum needed for basic physiological health.
Does the Navy method work well for athletes or bodybuilders?
Less reliably — because it estimates fat from waist and neck circumference, very muscular individuals with a thick neck or midsection from muscle (not fat) can get an inflated body fat estimate. A skinfold or DEXA measurement is more accurate for that group.
How often should I measure my body fat?
Every four to six weeks is enough, since changes are slow and day-to-day variations in water and food affect the tape. Measure under the same conditions each time and compare trends and not single readings.
Why did my estimate change when my weight did not?
This method uses circumferences and height, not weight. Losing inches at the waist lowers the estimate even when the scale stays the same, which can happen when you gain muscle and lose fat.
What is essential fat?
Essential fat is the minimum your body needs for normal function, and it is higher in women than in men. Staying in the essential range for long periods is not healthy, so it is not a target.
About this tool
This calculator uses the U.S. Navy circumference method to estimate body fat percentage from a few simple tape measurements. It's a widely used, no-equipment way to get a general estimate, though it's not as precise as clinical methods like DEXA or hydrostatic weighing.
Worked examples
The U.S. Navy method uses logarithms of your height and of a circumference measurement. For men the formula is 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450, with all measurements in centimetres. For women the waist, hip and neck are combined as (waist + hip − neck) and the constants differ.
- Man, 175 cm, neck 38 cm, waist 85 cm: an estimated 16.9% body fat, which falls in the fitness range.
- Woman, 165 cm, neck 32 cm, waist 75 cm, hip 98 cm: an estimated 28.9%, in the average range.
How measurements change the result
| Waist | Estimated body fat | Range |
|---|---|---|
| 75 cm | 8.4% | Athletic |
| 80 cm | 12.9% | Athletic |
| 85 cm | 16.9% | Fitness |
| 90 cm | 20.7% | Average |
| 95 cm | 24.1% | Average |
| 100 cm | 27.3% | Above average |
| Waist | Estimated body fat | Range |
|---|---|---|
| 65 cm | 23.8% | Fitness |
| 70 cm | 26.4% | Average |
| 75 cm | 28.9% | Average |
| 80 cm | 31.4% | Average |
| 85 cm | 33.8% | Above average |
| Height | Estimated body fat |
|---|---|
| 165 cm | 18.7% |
| 170 cm | 17.8% |
| 175 cm | 16.9% |
| 180 cm | 16.1% |
| 185 cm | 15.3% |
The waist is the most influential number, which is why measuring in the right place matters. A difference of a centimetre or two in how the tape sits can change the estimate by about a percentage point.
How to measure consistently
- Neck: just below the larynx, with the tape sloping slightly downward at the front.
- Waist (men): at the level of the navel. Waist (women): at the narrowest point, usually above the navel.
- Hips (women): at the widest point of the buttocks.
- Technique: stand relaxed, breathe out normally, keep the tape snug but not tight, and measure at the same time of day. Take each measurement twice and average them.
How far to trust the number
Tape-measure formulas are estimates, and a result can differ from a DEXA scan or hydrostatic weighing by several percentage points. They work best for tracking your own trend over time under the same conditions, and less well for comparing yourself with someone else. They are less reliable for very muscular or very lean people, older adults, pregnant women and children, who should not use this tool. The category labels are general fitness ranges and not medical thresholds. For health advice, speak to a doctor or other qualified professional.