Estimate your body fat percentage using the US Navy circumference method. Requires waist, neck, and hip measurements.
A Body Fat Calculator estimates the percentage of your total body weight that is made up of fat tissue, as opposed to lean mass such as muscle, bone, and water. Unlike BMI, which only considers height and weight, body fat percentage gives a more direct sense of body composition, which is why athletes, bodybuilders, and health-conscious individuals often track it alongside or instead of BMI to better understand their actual fitness progress.
This calculator commonly uses the U.S. Navy circumference method, which estimates body fat from measurements of neck, waist, and (for women) hip circumference, combined with height. For men: body fat % = 495 / (1.0324 − 0.19077×log10(waist−neck) + 0.15456×log10(height)) − 450. For women, an equivalent formula incorporates hip measurement as well, since fat distribution patterns differ between men and women.
Measure your neck and waist circumference with a flexible tape measure (and hip circumference if you are female), along with your height, then enter these values along with your gender. The calculator returns your estimated body fat percentage and the corresponding category, such as athletic, fitness, average, or above average.
Example 1: A man who is 178 cm tall with a 90 cm waist and 38 cm neck has an estimated body fat percentage in the high teens to low twenties, depending on the exact measurements, generally falling in an "average" fitness category.
Example 2: A woman who is 165 cm tall with a 75 cm waist, 95 cm hip, and 32 cm neck typically shows an estimated body fat percentage in the mid-to-high twenties, which commonly falls within a healthy range for women.
How accurate is the Navy circumference method? It is reasonably accurate for most people within a normal weight range, generally within a few percentage points of more advanced methods like DEXA scans, but it can be less reliable for people with very high muscle mass or unusually distributed body fat.
What is a healthy body fat percentage range? Healthy ranges vary by gender and age, but general guidelines suggest roughly 10–20% for men and 18–28% for women as typical fitness-to-average ranges, with athletes often falling below these ranges and essential fat minimums existing below which health risks increase.
Why do women naturally have higher body fat percentages than men? Women's bodies are biologically designed to carry more essential fat to support reproductive functions such as pregnancy and hormone regulation, which is why healthy body fat ranges for women are set noticeably higher than for men.
How does body fat percentage differ from BMI? BMI only uses height and weight and cannot distinguish muscle from fat, whereas body fat percentage directly estimates the proportion of fat tissue, which is why a very muscular person can have a high BMI but a low, healthy body fat percentage.
What is the most accurate way to measure body fat? DEXA scans and hydrostatic (underwater) weighing are considered gold-standard clinical methods, but they require specialized equipment; circumference methods, skinfold calipers, and bioelectrical impedance scales offer more accessible, though somewhat less precise, alternatives for everyday tracking.
Can body fat percentage change quickly? Meaningful changes in body fat typically take weeks to months of consistent diet and exercise changes to show up reliably, since day-to-day fluctuations are often driven by water retention and digestion rather than actual changes in fat tissue.
Does this tool account for where fat is stored on the body? The circumference method used here focuses on overall percentage rather than fat distribution, though waist circumference itself is a useful separate indicator, since abdominal (visceral) fat carries different health implications than fat stored elsewhere on the body.
Should I track body fat percentage instead of just weight? Tracking both together often gives a fuller picture, since weight alone doesn't reveal whether a change is coming from fat loss, muscle gain, or water shifts, while body fat percentage helps clarify what's actually changing in your body composition.
How does age affect typical body fat percentage? Body fat percentage tends to gradually rise with age even at a stable weight, largely because of natural muscle loss over time, which is why healthy body fat ranges are sometimes adjusted slightly upward for older age brackets compared with younger adults.
Can two people with the same weight and height have very different body fat percentages? Yes, differences in muscle mass, bone density, and genetics mean two people who are identical on paper by height and weight can have noticeably different body fat percentages, which is exactly why body fat is a more informative measure than weight or BMI alone.
Why does hydration status affect circumference-based body fat readings? Water retention can slightly change waist and neck measurements from day to day, so measuring at a consistent time, ideally first thing in the morning before eating or drinking, gives more comparable and reliable readings over repeated checks.