Body Fat Calculator
Estimate your body fat percentage using multiple methods.
Results
Estimated Body Fat
0%
About Body Fat Calculation
Body fat percentage is a measure of the proportion of fat in your body compared to lean tissue (muscles, bones, organs). It provides a more accurate picture of health than weight alone.
The US Navy method used in this calculator is a widely accepted estimation technique that requires only simple body measurements.
Frequently Asked Questions
How is body fat percentage measured?
This calculator uses the US Navy method, which estimates body fat based on measurements of your neck, waist, and hip circumference along with your height and gender.
What is a healthy body fat percentage?
For men, 10-20% is considered healthy. For women, 18-28% is healthy. Athletes typically have lower percentages, while obese individuals have higher ones.
How often should I measure body fat?
Body fat measurement once a month is sufficient for tracking changes. More frequent measurements can show normal daily fluctuations that are not meaningful.
Overview
Body fat percentage (BF%) is the share of total body mass that is fat tissue, and it gives a more direct picture of health risk than body weight or BMI alone. The WHO and the National Institutes of Health (NIH) use body fat ranges to define categories such as essential fat, athletes, fitness, average, and obese, and the American Council on Exercise (ACE) publishes the most widely cited cutoffs. For most adults, a healthy range is roughly 21 to 32 percent for women and 8 to 19 percent for men, though 'healthy' depends heavily on age, activity level, and individual factors.
There are several ways to estimate BF%. Laboratory methods such as DEXA (dual-energy X-ray absorptiometry), hydrostatic weighing (underwater densitometry), and BodPod (air displacement plethysmography) are the most accurate and are usually within 1 to 2 percentage points of the true value. They are also expensive and not always accessible. Skinfold calipers, used by trained technicians, can be accurate to within 3 to 4 percentage points when the right sites are measured with the right protocol. Bioelectrical impedance analysis (BIA), built into many bathroom scales and handheld devices, is convenient but can vary by 3 to 8 percentage points depending on hydration, recent meals, and device quality.
The US Navy Method is a popular middle ground: it is accurate to within about 3 to 4 percentage points for most people, requires only a tape measure, and is free. The method uses circumference measurements (neck, waist, and for women, hips) along with height, and applies separate formulas for men and women. It was developed by the US Navy in the 1980s to estimate body composition for service members. The calculator below uses these formulas. For best results, measure in the morning, before exercise or eating, with a flexible tape held snug but not tight.
Body fat is not just one number. Where the fat is carried matters: visceral fat around the abdomen is more strongly linked to metabolic risk than subcutaneous fat under the skin. A waist circumference above 102 cm (40 in) for men or 88 cm (35 in) for women is the WHO threshold for substantially increased risk. The CDC and the American Heart Association use these cutoffs as a simpler, often more telling marker than BF% alone.
How to use
- Measure height in centimeters or inches, neck circumference at the narrowest point, and waist at the navel (and hips for women).
- Enter sex, age, height, neck, waist, and (for women) hip circumference into the form.
- Submit to see the estimated body fat percentage and the matching ACE category.
- Repeat measurements in the same conditions (morning, hydrated, before exercise) to track changes over time.
Formula
Interpreting your results
For adult men, the ACE categories are: essential fat 2-5%, athletes 6-13%, fitness 14-17%, average 18-24%, and obese 25%+. For adult women: essential fat 10-13%, athletes 14-20%, fitness 21-24%, average 25-31%, and obese 32%+. Numbers below the essential fat range can disrupt hormones and should be discussed with a clinician, especially in adolescents and women of reproductive age. The NIH and CDC note that body fat percentages within these ranges are associated with lower average risk for cardiovascular and metabolic disease, but trends over time are more informative than any single reading.