How to Calculate Body Fat Percentage

Body fat percentage is one of the most accurate measures of physical fitness and health. Unlike weight alone, it tells you how much of your body is fat versus lean mass -- muscle, bone, organs, and water. Knowing your number helps you set smarter fitness goals and track real progress.

This guide explains the most common methods for calculating body fat percentage, what healthy ranges look like by age and sex, and how to use the number to guide your training and nutrition.

What Is Body Fat Percentage?

Body fat percentage is the proportion of your total body weight that comes from fat tissue. The rest -- everything that is not fat -- is called lean body mass.

For example, if you weigh 80 kg and carry 16 kg of fat, your body fat percentage is 20%.

Some fat is essential. Your body needs it for hormone production, organ protection, and temperature regulation. The goal is not to eliminate fat but to stay within a healthy range for your age and sex.

Methods for Calculating Body Fat Percentage

Skinfold Calipers

A trained practitioner uses calipers to pinch and measure the thickness of skin folds at specific sites -- typically the abdomen, thigh, chest, and tricep. These measurements are entered into a formula to estimate total body fat. Accuracy depends on technique and the formula used. When done correctly, skinfold testing is reasonably accurate for most people.

Body Circumference Measurements (Navy Method)

The US Navy method uses a tape measure to calculate body fat from circumference measurements at specific sites. For men, it uses neck and abdomen circumference. For women, it uses neck, waist, and hip circumference. The formula is straightforward and requires no equipment beyond a measuring tape, making it the easiest method to use at home.

For men: % Body Fat = 86.010 x log10(abdomen - neck) - 70.041 x log10(height) + 36.76

For women: % Body Fat = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387

DEXA Scan

Dual-energy X-ray absorptiometry (DEXA) is considered one of the most accurate methods available. It uses low-dose X-rays to distinguish between fat mass, lean mass, and bone density across your entire body. DEXA scans are available at sports clinics and medical facilities and typically cost between $50 and $150.

Hydrostatic Weighing

Also called underwater weighing, this method measures body density by comparing your weight on land to your weight when fully submerged in water. Fat is less dense than muscle, so the difference reveals body composition. It is highly accurate but requires specialist equipment and is rarely used outside research settings.

Bioelectrical Impedance Analysis (BIA)

BIA devices send a small electrical current through the body. Fat and muscle conduct electricity differently, allowing the device to estimate body composition. Consumer smart scales and handheld devices use BIA. Results can vary significantly based on hydration levels, time of day, and whether you have eaten or exercised recently. Use BIA for tracking trends rather than precise measurements.

Healthy Body Fat Percentage Ranges

Healthy ranges differ between men and women due to physiological differences in essential fat storage.

For Men

Essential fat: 2% to 5%

Athletic: 6% to 13%

Fitness: 14% to 17%

Average: 18% to 24%

Obese: 25% and above

For Women

Essential fat: 10% to 13%

Athletic: 14% to 20%

Fitness: 21% to 24%

Average: 25% to 31%

Obese: 32% and above

These ranges are general guidelines. Age also plays a role -- body fat naturally increases with age even without changes in diet or activity. Older adults typically carry slightly more fat at the same fitness level as younger individuals.

Body Fat vs BMI -- What Is the Difference?

BMI (Body Mass Index) measures your weight relative to your height. It does not distinguish between fat and muscle. A muscular athlete may have a high BMI but a low body fat percentage, while someone with a normal BMI may carry an unhealthy amount of fat.

Body fat percentage is a more precise indicator of health and fitness than BMI alone. Using both together gives a more complete picture.

How to Lower Your Body Fat Percentage

Reducing body fat requires a consistent calorie deficit combined with preserving or building lean muscle mass.

Nutrition: Prioritise protein to protect muscle during a calorie deficit. Aim for 1.6 to 2.2 grams of protein per kilogram of body weight daily.

Strength training: Resistance training builds and maintains lean muscle, which increases your resting metabolic rate and helps you burn more fat over time.

Cardio: Aerobic exercise increases calorie burn and supports fat loss, particularly when combined with strength training.

Consistency: Body fat reduction is gradual. A realistic rate of fat loss is 0.5% to 1% of body weight per week without losing significant muscle mass.

Tracking Progress Over Time

Body fat percentage fluctuates day to day due to hydration, digestion, and other factors. For meaningful tracking, measure under the same conditions -- same time of day, same hydration level, same method -- and compare results every two to four weeks rather than daily.

Progress photos, strength metrics, and how clothes fit are equally valuable indicators of body composition change.