Body Fat Calculator

What is Body Fat Percentage?

Body fat percentage is the proportion of fat tissue relative to your total body weight. Unlike BMI which only considers height and weight, body fat percentage distinguishes between lean mass (muscle, bone, organs) and fat mass, giving a more accurate picture of your body composition.

How the U.S. Navy Method Works

The U.S. Navy developed a circumference-based method that estimates body fat using measurements of the neck, waist, and (for women) hips. This method has been validated against hydrostatic weighing and DEXA scans, making it a reliable field measurement technique. The formula uses logarithmic equations that account for the relationship between body circumference and body density.

Healthy Body Fat Ranges

For men: essential fat 2-5%, athletes 6-13%, fitness 14-17%, average 18-24%, above average 25%+. For women: essential fat 10-13%, athletes 14-20%, fitness 21-24%, average 25-31%, above average 32%+. Women naturally carry more essential fat due to reproductive requirements.

Why Body Fat Matters More Than Weight

Two people can weigh the same but have completely different health profiles. A muscular athlete at 90kg with 12% body fat is metabolically healthier than a sedentary person at 90kg with 30% body fat. Body fat distribution also matters — visceral fat around organs is more dangerous than subcutaneous fat under the skin.

Limitations of the Navy Method

The Navy method may underestimate body fat in very lean individuals and overestimate in very obese individuals. It does not directly measure visceral fat. For the most accurate results, measure at the same time of day under consistent conditions.

Body Fat Percentage by Age — What Is Normal?

Body fat naturally increases with age. A 25-year-old man with 18% body fat is in the fitness range, while a 55-year-old man with 22% body fat may still be in the healthy average range. The American Council on Exercise provides age-adjusted body fat charts that account for these natural changes.

How to Lower Body Fat Percentage

Sustainable fat loss requires a moderate calorie deficit (300-500 calories below TDEE), adequate protein intake (1.6-2.2g per kg of body weight), and resistance training to preserve muscle mass. Crash dieting often leads to muscle loss, which lowers BMR and makes long-term fat loss harder. Track your progress with body measurements, not just the scale.

Body Fat Calculator vs DEXA Scan — How Accurate?

The U.S. Navy method is about 3-5% accurate compared to DEXA (the gold standard). It tends to slightly underestimate body fat in lean individuals and overestimate in obese individuals. For most people tracking trends over time, the Navy method provides sufficient accuracy without the cost or radiation exposure of clinical methods.