What is a healthy body fat percentage?

For men, useful fat is 2-5%, athletes are 6-13%, fitness is 14-17%, average is 18-24%, and obese is 25%+. For women, useful fat is 10-13%, athletes are 14-20%, fitness is 21-24%, average is 25-31%, and obese is 32%+.

How accurate is the US Navy body fat method?

The US Navy method is accurate to within 1-3% for most people when measurements are taken correctly. It's most accurate for people with average body compositions and may be less accurate for very muscular or very lean individuals. It's more accurate than BMI alone.

How should I take body measurements for the most accurate result?

Measure first thing in the morning before eating. Use a flexible tape measure pulled snug but not compressing the skin. Measure your neck at the narrowest point below the Adam's apple, your waist at the navel, and hips (women) at the widest point of the buttocks. Take each measurement twice and average the results.

How often should I measure my body fat?

Measure once every 2-4 weeks rather than daily. Body fat changes slowly, even with consistent training and diet, expect to lose only 0.5-1% body fat per month. Always measure under the same conditions (time of day, hydration level) for the most consistent comparisons.

What is the difference between body fat percentage and BMI?

BMI uses only height and weight and cannot distinguish between muscle and fat. Body fat percentage estimates actual fat tissue relative to total body weight. A muscular person may have a high BMI but low body fat. Body fat percentage provides a more accurate picture of fitness and health risk.

Body Fat Calculator

Estimate your body fat percentage using the US Navy method. This calculator uses your gender, age, height, neck, waist, and hip measurements to provide an accurate body fat estimate along with your fitness category.

By InstaCalcs Team·Reviewed April 25, 2026·Report an issue

Gender

Height (cm)

Neck Circumference (cm)

Waist Circumference (cm)

Weight (kg), optional

Body Fat

23.5%

Body Fat Categories (Men)

Essential Fat

Athletes

Fitness

Average

Obese

Essential Fat

2-5%

Athletes

6-13%

Fitness

14-17%

Average

18-24%

Obese

25-45%

How to use

Select your gender and enter your height, neck circumference, and waist circumference in centimeters. Women also need to enter hip circumference. Measure your waist at the navel, neck at the narrowest point, and hips at the widest point. The calculator uses the US Navy body fat formula to estimate your body fat percentage and fitness category.

US Navy Method Formula

Men: BF% = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76

Women: BF% = 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387

Categories for men: Essential Fat (2-5%), Athletes (6-13%), Fitness (14-17%), Average (18-24%), Obese (25%+). For women: Essential Fat (10-13%), Athletes (14-20%), Fitness (21-24%), Average (25-31%), Obese (32%+). The US Navy method is considered reasonably accurate and correlates well with more expensive methods like DEXA scans.

When this calculator helps

Body fat percentage is a far more meaningful health indicator than weight alone. Two people at the same weight can have vastly different body compositions, one lean and muscular, the other carrying excess fat. This calculator helps athletes track progress during training cycles, dieters verify they are losing fat rather than muscle, and anyone curious about their fitness level. The US Navy method requires only a tape measure, making it accessible at home without expensive equipment like DEXA scans or calipers.

Examples

Example 1: Active Male

A 30-year-old man, 5'11" tall, with a 15.5-inch neck and 33-inch waist. Using the US Navy formula, his estimated body fat is approximately 15%, placing him in the fitness category. He would need to reduce his waist to about 31 inches to reach the athlete range of 6-13%.

Example 2: Woman Starting a Fitness Program

A 28-year-old woman, 5'5" tall, with a 13-inch neck, 30-inch waist, and 38-inch hips. Her estimated body fat is about 27%, placing her in the average category. With consistent exercise and a modest calorie deficit, she could reach the fitness range of 21-24% in approximately 3-4 months.

Example 3: Competitive Athlete

A 25-year-old male runner, 5'9" tall, with a 15-inch neck and 29-inch waist. His estimated body fat is roughly 10%, well within the athlete category. Maintaining this level requires disciplined nutrition and consistent training, going below 5% is generally unsustainable and unhealthy long-term.

Things to watch

•Always measure at the same time of day, preferably morning, to minimize fluctuations from food, water, and bloating.
•Do not pull the tape measure too tight, it should be snug against the skin without compressing the tissue underneath.
•The US Navy method may underestimate body fat in people who carry fat primarily in their limbs rather than their waist.
•Very low body fat levels (under 5% for men, under 13% for women) can disrupt hormones and weaken the immune system.
•For the most accurate tracking, have the same person take your measurements each time using the same tape measure.

Sources and methodology

Last reviewed: April 25, 2026. We review formulas, default assumptions, and examples against public references when a formal source applies.

Method: This calculator uses the formula explained on this page, then checks default assumptions and examples against the references listed below.

•Adult BMI Calculator, Centers for Disease Control and Prevention
•Calculating BMI, Centers for Disease Control and Prevention

Found something off? Send a correction with the page URL, inputs, result, and expected result.

Common questions

What is a healthy body fat percentage?: For men, useful fat is 2-5%, athletes are 6-13%, fitness is 14-17%, average is 18-24%, and obese is 25%+. For women, useful fat is 10-13%, athletes are 14-20%, fitness is 21-24%, average is 25-31%, and obese is 32%+.
How accurate is the US Navy body fat method?: The US Navy method is accurate to within 1-3% for most people when measurements are taken correctly. It's most accurate for people with average body compositions and may be less accurate for very muscular or very lean individuals. It's more accurate than BMI alone.
How should I take body measurements for the most accurate result?: Measure first thing in the morning before eating. Use a flexible tape measure pulled snug but not compressing the skin. Measure your neck at the narrowest point below the Adam's apple, your waist at the navel, and hips (women) at the widest point of the buttocks. Take each measurement twice and average the results.
How often should I measure my body fat?: Measure once every 2-4 weeks rather than daily. Body fat changes slowly, even with consistent training and diet, expect to lose only 0.5-1% body fat per month. Always measure under the same conditions (time of day, hydration level) for the most consistent comparisons.
What is the difference between body fat percentage and BMI?: BMI uses only height and weight and cannot distinguish between muscle and fat. Body fat percentage estimates actual fat tissue relative to total body weight. A muscular person may have a high BMI but low body fat. Body fat percentage provides a more accurate picture of fitness and health risk.