Body Fat Percentage: How to Measure and Interpret

Your body fat percentage tells you what proportion of your total body weight comes from fat tissue. Unlike BMI, which only considers weight and height, body fat percentage distinguishes between the mass that is fat and the mass that is muscle, bone, water, and organs. This distinction makes it a far more informative measure of body composition and overall health.

In this guide, you will learn what body fat percentage means, how to measure it using several different methods, what ranges are considered healthy for your age and sex, and how to interpret your results in a way that supports your health and fitness goals.

What Is Body Fat Percentage?

Body fat percentage is the portion of your total body weight that consists of fat tissue, expressed as a percentage. If you weigh 180 pounds and have 36 pounds of fat, your body fat percentage is 20%. The remaining 144 pounds, your lean body mass, includes muscle, bone, water, connective tissue, and internal organs.

Body fat serves critical biological functions. It insulates your body against temperature extremes, cushions and protects internal organs, stores energy for periods when caloric intake is insufficient, and plays essential roles in hormone production and regulation. The goal is not to eliminate body fat but to maintain it within a range that supports good health without increasing disease risk.

Essential Fat vs Storage Fat

Body fat is divided into two categories. Essential fat is the minimum amount required for normal physiological function. It resides in the bone marrow, heart, lungs, liver, spleen, kidneys, muscles, and central nervous system. For men, essential fat is approximately 2% to 5% of body weight. For women, it is 10% to 13%, with the higher requirement supporting reproductive function and hormonal health.

Storage fat accumulates beneath the skin (subcutaneous fat) and around internal organs (visceral fat). Subcutaneous fat serves as an energy reserve and provides insulation. Visceral fat, which surrounds organs in the abdominal cavity, is metabolically active and associated with higher health risks when present in excess. Reducing visceral fat specifically improves cardiovascular health markers even when total body weight changes only modestly.

How to Measure Body Fat Percentage

Several methods exist for measuring body fat, ranging from simple at-home techniques to sophisticated laboratory tests. Each method involves trade-offs between accuracy, cost, and convenience. Understanding these trade-offs helps you choose the right approach for your situation.

Measurement Methods Comparison

For most people, the best approach is to pick one method and use it consistently. The absolute number matters less than the trend over time. If your body fat percentage is decreasing month over month using the same measurement method, you are making progress regardless of whether the number is perfectly precise.

The Navy Method Formula

The U.S. Navy body fat estimation method uses circumference measurements and height to calculate body fat percentage. It requires only a flexible tape measure and takes less than five minutes. The formulas differ for men and women because fat distribution patterns differ between sexes.

For men, the formula uses waist and neck circumference along with height:

For women, the formula adds a hip circumference measurement:

All measurements are in inches for these formulas. Measure the waist at the narrowest point (typically at the navel), the neck just below the larynx, and the hips at the widest point.

Step-by-Step Navy Method Calculation

Here is a worked example for a man who is 70 inches tall with a 34-inch waist and a 15.5-inch neck:

1. Calculate waist minus neck: 34 - 15.5 = 18.5 inches
2. Find log₁₀(18.5): 1.2672
3. Find log₁₀(70): 1.8451
4. Apply the formula: 86.010 x 1.2672 - 70.041 x 1.8451 + 36.76
5. Calculate: 109.00 - 129.23 + 36.76 = 16.5%

This result of 16.5% body fat falls within the fitness range for an adult man, indicating a healthy level of body fat that is below average but well above essential fat levels.

Healthy Body Fat Ranges

Healthy body fat ranges differ significantly between men and women and shift gradually with age. Women naturally carry more essential fat to support reproductive function, which is why their healthy ranges are approximately 8% to 10% higher than men's at every age. As both men and women age, body fat tends to increase even when weight remains stable because muscle mass gradually decreases.

Body Fat Percentage Ranges by Age and Sex

These ranges are general guidelines based on classifications from the American Council on Exercise and similar organizations. Individual health depends on many factors beyond body fat percentage, including cardiovascular fitness, blood markers, family history, and lifestyle habits.

Real-World Body Fat Examples

Example 1: Competitive Runner

Aisha is a 28-year-old distance runner who competes in half marathons. She is 5 feet 6 inches tall, weighs 128 pounds, and her DEXA scan shows 17% body fat. This places her in the athletic range for women her age. Her lean body mass is approximately 106 pounds, which includes a strong proportion of lower body muscle developed through years of running.

Aisha's body fat level supports her athletic performance without compromising her hormonal health. She maintains regular menstrual cycles, which is an important indicator that her body fat is not too low. Her coach monitors her body composition quarterly to ensure that intense training blocks do not push her below the threshold where performance and health begin to decline.

Example 2: Strength Training Enthusiast

Daniel is 35 years old, stands 5 feet 11 inches tall, and weighs 195 pounds. He has been strength training consistently for eight years. His body fat percentage, measured with seven-site skinfold calipers at his gym, is 14%. This means he carries approximately 27 pounds of fat and 168 pounds of lean mass.

Daniel's BMI of 27.2 technically classifies him as overweight, but his body fat percentage tells a very different story. His 14% places him in the fitness range for men, reflecting his above-average muscle mass. This example demonstrates why body fat percentage provides more useful information than BMI alone for people who lift weights regularly.

Example 3: Health-Conscious Parent

Laura is 42 years old, 5 feet 4 inches tall, and weighs 155 pounds. She exercises moderately, walking daily and attending a yoga class twice a week. Her bioelectrical impedance scale at home reads 29% body fat, placing her in the average range for women her age.

Laura sets a goal to reduce her body fat to 25% over six months by adding two strength training sessions per week and modestly reducing her caloric intake by 300 calories per day. After six months, she weighs 148 pounds with 25% body fat. She lost 10 pounds of fat while gaining 3 pounds of lean mass. This approach, combining resistance training with a moderate deficit, is the most effective strategy for improving body composition without extreme measures.

How to Reduce Body Fat Safely

Reducing body fat requires creating a caloric deficit while preserving as much lean muscle mass as possible. The distinction between losing weight and losing fat is critical. Crash diets that create extreme caloric deficits often cause significant muscle loss along with fat loss, which worsens body composition even as the number on the scale drops.

• Create a moderate caloric deficit. Aim for 250 to 500 calories below your maintenance level. This produces steady fat loss of approximately 0.5 to 1 pound per week without triggering the metabolic slowdown associated with severe restriction.
• Prioritize protein intake. Consuming 0.7 to 1.0 grams of protein per pound of body weight daily helps preserve muscle mass during a deficit. Protein also increases satiety, making it easier to sustain a moderate deficit.
• Include resistance training. Lifting weights or performing bodyweight exercises two to four times per week signals your body to maintain muscle tissue. Without resistance training, a significant portion of weight loss comes from muscle rather than fat.
• Add cardiovascular exercise strategically. Moderate cardio such as brisk walking, cycling, or swimming supports fat loss by increasing caloric expenditure. Excessive cardio combined with severe caloric restriction can accelerate muscle loss.
• Sleep seven to nine hours nightly. Poor sleep increases cortisol levels and hunger hormones, both of which promote fat storage and make it harder to maintain a caloric deficit.

Tips for Accurate Body Fat Tracking

Consistency in measurement conditions matters more than the method you choose. Small variations in hydration, time of day, and recent meals can cause readings to fluctuate by several percentage points, creating misleading impressions of progress or regression.

• Measure at the same time of day. Morning measurements before eating and after using the bathroom provide the most consistent baseline because hydration and food intake are at their most predictable.
• Use the same method every time. Switching between calipers, BIA scales, and the Navy method makes comparison meaningless. Pick one and stick with it.
• Track monthly, not daily. Daily fluctuations in body fat readings are noise. Monthly measurements reveal the actual trend of your body composition changes.
• Record all related data. Log your body weight, circumference measurements, and how clothing fits alongside body fat readings. These data points together paint a clearer picture than any single number.

Common Mistakes to Avoid

• Obsessing over a single number. Body fat percentage is an estimate, not an exact measurement. A reading of 22% does not mean you have precisely 22% body fat. Focus on the direction of change over time rather than the absolute value on any given day.
• Comparing yourself to fitness models or athletes. The body fat levels displayed in fitness media are often achieved through temporary dehydration, lighting tricks, or unsustainable practices. A healthy body fat percentage for everyday life is significantly higher than what you see on magazine covers.
• Pursuing extremely low body fat. Dropping body fat below essential levels causes hormonal disruption, weakened immunity, fatigue, and increased injury risk. Even competitive bodybuilders only maintain contest-level body fat for brief periods.
• Ignoring the role of muscle. Losing 10 pounds of fat while gaining 5 pounds of muscle means the scale only shows a 5-pound loss, but your body composition has improved dramatically. Relying solely on scale weight misses this important transformation.
• Measuring after inconsistent conditions. Exercising, eating, or drinking before a measurement can significantly alter the result. If you measured fasted last month and post-meal this month, the comparison is unreliable.

Last updated: February 23, 2026