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A body fat calculator estimates the percentage of your total body weight that is stored as fat. Knowing your body fat percentage gives you a much clearer picture of your fitness than weight or BMI alone, because it distinguishes between fat mass and lean mass (muscle, bone, water, and organs). This calculator offers five different estimation methods so you can compare results and get a more reliable reading. The US Navy method uses waist, neck, and hip circumference measurements. The BMI-based method uses a statistical formula from your height, weight, and age. The BIA estimate approximates what an impedance device would report. The Jackson-Pollock 3-site and 7-site methods use skinfold caliper measurements for the most precise field estimates. All five results are displayed side by side with body fat category classifications (essential, athlete, fitness, average, above average) so you can see where you fall. Everything runs in your browser with no data uploaded and no account required.
Done with the Body Fat Calculator? Try this next:
BMI Calculator →Select imperial (lbs/inches) or metric (kg/cm), then enter your gender, age, weight, and height. These basic stats are used by the BMI-based and BIA estimation methods.
Measure your waist circumference at the navel, neck circumference just below the larynx, and (for females) hip circumference at the widest point. Use a flexible tape measure and keep it snug but not tight.
If you have a skinfold caliper, expand the Skinfold Measurements section. For the 3-site method, males measure chest, abdomen, and thigh; females measure tricep, suprailiac, and thigh. For the 7-site method, fill in all seven fields.
The calculator shows your estimated body fat percentage, fat mass, lean mass, and BMI. The category chart shows where your result falls: essential fat, athlete, fitness, average, or above average.
The comparison table and visual bars show results from every method that has enough data. A range and average across all valid methods gives you a more reliable estimate than any single formula.
The insights panel flags results outside healthy ranges and suggests actions. The method descriptions explain what each formula measures, its accuracy, and when to use it.
Body Fat Calculator estimates your body fat percentage using 5 methods: US Navy, Jackson-Pollock 3 and 7-site, BIA, and BMI-based. Compare all results side by side.
Males: BF% = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450
A male measuring 5'10" (177.8 cm) tall with a 34-inch (86.4 cm) waist and a 15-inch (38.1 cm) neck.
A female measuring 5'6" (167.6 cm) tall with a 29-inch (73.7 cm) waist, 37-inch (94.0 cm) hip, and 13-inch (33.0 cm) neck.
An athletic male measuring 6'0" (182.9 cm) tall with a 31-inch (78.7 cm) waist and a 16-inch (40.6 cm) neck.
| Category | Males (20 to 39) | Males (40 to 59) | Females (20 to 39) | Females (40 to 59) |
|---|---|---|---|---|
| Essential Fat | 2 to 5% | 2 to 5% | 10 to 13% | 10 to 13% |
| Athletic | 6 to 13% | 7 to 15% | 14 to 20% | 15 to 21% |
| Fitness | 14 to 17% | 16 to 20% | 21 to 24% | 22 to 27% |
| Average | 18 to 24% | 21 to 25% | 25 to 31% | 28 to 34% |
| Obese | 25% and above | 26% and above | 32% and above | 35% and above |
Ranges are based on American Council on Exercise (ACE) classifications. Body fat naturally increases with age. Essential fat is the minimum required for basic physiological function.
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</p>Healthy body fat ranges depend on gender. For males: athletes typically carry 6 to 13%, fitness enthusiasts 14 to 17%, average is 18 to 24%, and above 25% is considered above average. For females: athletes typically carry 14 to 20%, fitness enthusiasts 21 to 24%, average is 25 to 31%, and above 32% is considered above average. Essential fat (the minimum needed for basic health) is 2 to 5% for males and 10 to 13% for females.
Among the methods in this calculator, the Jackson-Pollock 7-site skinfold method is generally considered the most accurate field method, with an error margin of plus or minus 2 to 3 percentage points compared to hydrostatic weighing. The US Navy method is the most practical for home use with an error margin of plus or minus 3 to 4 percentage points. For clinical accuracy, DEXA scans and hydrostatic weighing are the gold standard but require specialized equipment.
Use a skinfold caliper. Pinch the skin and underlying fat (not muscle) between your thumb and forefinger, then place the caliper jaws about 1 cm from your fingers. Take the reading after 2 seconds. Measure each site 2 to 3 times and use the average. Always measure on the right side of the body. Common mistakes include pinching too little skin, placing the caliper too close to the fingers, and measuring while the muscle is flexed.
Each method uses a different approach to estimate body fat. The Navy method uses circumference ratios, skinfold methods measure subcutaneous fat thickness, and BMI-based methods use statistical population averages. None of them directly measure total body fat. Factors like muscle mass, body shape, fat distribution, and hydration affect each method differently. A spread of 3 to 5 percentage points between methods is normal.
Body fat percentage is more useful for assessing fitness and health risk because it distinguishes between fat and muscle. BMI only considers height and weight, so a muscular person can have a 'overweight' BMI despite having low body fat. However, BMI is easier to calculate and is still useful for population-level health screening. Ideally, use both metrics together for a more complete picture.
Measure every 2 to 4 weeks if you are actively trying to change your body composition. More frequent measurements introduce noise from hydration changes, meal timing, and measurement inconsistency. Always measure under the same conditions: same time of day, same hydration level, same person taking the measurements. Track the trend over months rather than reacting to any single reading.
No. Spot reduction (losing fat from one specific body part) is a persistent myth. When you lose fat, your body draws from fat stores throughout the body based on genetics, hormones, and gender. The most effective approach is a consistent calorie deficit combined with resistance training to preserve muscle. Over time, fat loss will occur across your entire body, including stubborn areas.
The US Navy formula for males is: Body Fat % = 495 / (1.0324 - 0.19077 * log10(waist - neck) + 0.15456 * log10(height)) - 450. For females: Body Fat % = 495 / (1.29579 - 0.35004 * log10(waist + hip - neck) + 0.22100 * log10(height)) - 450. All measurements are in centimeters. This formula was developed by Hodgdon and Beckett at the Naval Health Research Center.
Yes. Every calculation runs entirely in your browser. Your body measurements are never sent to any server, no cookies are set, and no account is required. You can safely enter your real measurements without any privacy concerns.
FreeToolPark. "Body Fat Calculator." FreeToolPark, 2026, www.freetoolpark.com/tools/body-fat-calculator. Accessed April 14, 2026.