Body Fat Calculator

To calculate your body fat percentage using this calculator, you will need a flexible tape measure and a few minutes to take accurate measurements. Begin by selecting your gender, as the formula differs for men and women. Then choose your preferred unit system, either imperial (inches) or metric (centimeters).

Measuring Your Waist: Stand relaxed with your feet shoulder-width apart. Locate your navel and wrap the tape measure horizontally around your abdomen at this level. Do not suck in your stomach or hold your breath. The tape should be snug against your skin without compressing it. Record the measurement after a normal exhale.

Measuring Your Neck: Tilt your head slightly back and measure around the narrowest part of your neck, which is typically just below your larynx (Adam's apple). Keep the tape measure perpendicular to the long axis of your neck. Avoid measuring over clothing or jewelry.

Measuring Your Hips (Women Only): Stand with feet together and measure around the widest part of your buttocks and hips. Keep the tape parallel to the floor and ensure it passes over the fullest part of your hip bones. Do not compress your hips or pull the tape too tightly.

Once you have entered all measurements, click the calculate button. The calculator will display your estimated body fat percentage, your fitness category, and a breakdown of your fat mass and lean mass. For the most consistent results, take measurements at the same time of day, preferably in the morning before eating and after using the restroom. Take each measurement twice and use the average for best accuracy.

Body fat percentage represents the proportion of your total body weight that consists of fat tissue. Unlike body weight alone, which includes muscle, bone, water, and organs, body fat percentage tells you specifically how much of your body is composed of fat. This measurement provides a more accurate picture of your body composition and overall fitness level than the scale alone.

Essential Fat vs. Storage Fat: Your body contains two types of fat with distinct purposes. Essential fat is required for normal physiological function, including hormone regulation, vitamin absorption, nerve insulation, and protection of vital organs. Men require 2 to 5 percent essential body fat, while women need 10 to 13 percent due to reproductive and hormonal requirements. Storage fat accumulates beneath the skin (subcutaneous fat) and around organs (visceral fat) as an energy reserve. While some storage fat is normal and healthy, excessive amounts increase health risks.

Healthy Ranges by Gender and Age: Optimal body fat percentages vary significantly between men and women due to biological differences. For men aged 20 to 39, a healthy range is typically 8 to 19 percent, with 14 to 17 percent considered fit. Women in the same age group should aim for 21 to 32 percent, with 21 to 24 percent being fit. As we age, body fat naturally increases while muscle mass decreases. Men aged 40 to 59 may have healthy percentages of 11 to 22 percent, while women of the same age range from 23 to 33 percent. After age 60, ranges increase further as maintaining muscle becomes more challenging.

Measurement Methods Compared: Several techniques exist for measuring body fat, each with different accuracy levels and accessibility. The US Navy circumference method used by this calculator provides a convenient estimate using only a tape measure, with accuracy within 3 to 4 percent of laboratory methods. Skinfold calipers measure subcutaneous fat at specific body sites and require trained technicians for accuracy. Bioelectrical impedance analysis (BIA) sends a small electrical current through the body and is found in many bathroom scales, though hydration levels significantly affect results. Hydrostatic (underwater) weighing measures body density by water displacement and was long considered the gold standard. DEXA (dual-energy X-ray absorptiometry) scans provide the most accurate measurements by differentiating between bone, lean tissue, and fat mass, but require specialized medical equipment.

Body fat distribution matters as much as the total amount. Fat stored around the abdomen, known as visceral fat, poses greater health risks than fat stored in the hips and thighs. Visceral fat surrounds internal organs and releases inflammatory compounds that can contribute to chronic disease. This is one reason why waist measurements are included in body fat calculations and health assessments. Research shows that waist circumference above 40 inches for men or 35 inches for women indicates elevated cardiovascular and metabolic risk regardless of overall body fat percentage.

Several factors influence your body fat percentage including genetics, age, gender, diet, and physical activity level. As people age, they tend to lose muscle mass and gain fat, even if their weight remains stable. This process, called sarcopenia, can result in a person having a normal weight but an unhealthy body composition. Regular exercise, particularly strength training, helps maintain muscle mass and keep body fat levels in a healthy range throughout life.

Male Athlete Example: Marcus is a 28-year-old competitive cyclist who is 71 inches tall with a 15.5 inch neck and 30 inch waist. His calculated body fat percentage is approximately 11%, placing him in the athlete category (6 to 13 percent for men). At this level, he has visible muscle definition, prominent vascularity, and minimal subcutaneous fat. His low body fat supports his athletic performance but requires careful attention to nutrition to maintain adequate energy and hormone levels.

Female Fitness Example: Sarah is a 32-year-old personal trainer measuring 66 inches tall with a 12.5 inch neck, 27 inch waist, and 37 inch hips. Her estimated body fat is approximately 22%, which falls in the fitness category for women (21 to 24 percent). She maintains visible muscle tone and a lean physique while having adequate body fat for healthy hormone function, regular menstruation, and sustained energy for her active lifestyle.

Average Adult Example: David is a 45-year-old office worker who is 69 inches tall with a 16 inch neck and 36 inch waist. His body fat percentage calculates to approximately 22%, placing him in the average category for men (18 to 24 percent). While this is within a normal range, David could improve his body composition through increased physical activity and dietary modifications. Reducing his waist circumference by a few inches would move him into the fitness category and potentially reduce his risk of metabolic conditions.

Health Improvement Example: Jennifer is a 38-year-old mother of two measuring 64 inches tall with a 13 inch neck, 33 inch waist, and 42 inch hips. Her calculated body fat is approximately 35%, in the obese category for women (above 32 percent). Her healthcare provider has recommended lifestyle changes to reduce her body fat for better cardiovascular health. By combining regular exercise with improved nutrition, she can work toward the average or fitness range over time.

The U.S. Navy developed this body fat estimation method in the 1980s as a simple way to assess the fitness of military personnel without expensive equipment. The formula uses logarithmic calculations based on body circumference measurements and height.

All measurements should be in centimeters for this formula. The calculator automatically converts imperial measurements to metric before applying the formula.

Body Composition Matters More Than Weight: The number on the scale does not tell the full story of your health. Two people at the same weight can have dramatically different body compositions, health risks, and physical capabilities. Focus on building and maintaining lean muscle mass while reducing excess body fat rather than simply trying to lose weight. Muscle tissue burns more calories at rest, supports metabolic health, protects joints, and maintains functional independence as you age.

Strength Training Is Essential: Resistance training is one of the most effective tools for improving body composition at any age. Lifting weights or performing bodyweight exercises 2 to 4 times per week stimulates muscle protein synthesis, increases bone density, improves insulin sensitivity, and creates metabolic benefits that persist long after your workout ends. You do not need to become a bodybuilder: even moderate strength training preserves muscle mass during fat loss and reverses the muscle decline that naturally occurs with aging.

Nutrition for Body Composition: Protein intake is crucial for both building muscle and losing fat. The American College of Sports Medicine recommends 1.2 to 2.0 grams of protein per kilogram of body weight daily for active individuals. Distribute protein intake across meals for optimal muscle protein synthesis. Emphasize whole foods including lean proteins, vegetables, fruits, whole grains, and healthy fats. Avoid extreme diets that eliminate entire food groups or create severe caloric deficits, as these approaches often result in muscle loss and metabolic adaptation.

Sources: Body fat percentage guidelines and health recommendations referenced from the American Council on Exercise (ACE), American College of Sports Medicine (ACSM), and the National Institutes of Health (NIH).

This body fat calculator provides estimates for educational and informational purposes only. The US Navy method, while validated for use in fitness assessments, cannot account for individual variations in body composition. Results should not be used to diagnose any health condition or replace professional medical evaluation.

Body fat percentage is just one indicator of health among many. Factors such as blood pressure, cholesterol levels, blood glucose, cardiovascular fitness, and mental well-being all contribute to overall health status. Individuals with certain conditions including pregnancy, edema, or unusual body proportions may receive inaccurate results from circumference-based methods.

If you have concerns about your body composition or overall health, consult with a healthcare provider or certified fitness professional. They can provide more accurate assessments using advanced methods and offer personalized guidance based on your individual health profile, medical history, and goals.