What is the US Navy Circumference Method?

It is a mathematical formula developed by the US Navy that uses height and neck, waist, and hip circumferences to estimate body fat percentage.

Why does the formula require hip measurements for women but not men?

Biologically, women store more subcutaneous fat around the hips and thighs (gynoid distribution), while men store fat primarily around the midsection (android distribution).

What is essential fat?

Essential fat is the minimum fat required for basic physiological functions, hormone regulation, and insulation (approx. 3% for men and 12% for women).

What is visceral fat?

Visceral fat is fat stored deep inside the abdominal cavity around major organs, which is highly linked to metabolic issues and heart disease.

Does this calculator tell me my lean mass?

Yes. The calculator calculates your Fat Mass and Lean Mass weights based on your total body weight and body fat percentage.

How do I lower my body fat percentage?

Maintain a moderate caloric deficit, consume adequate protein to preserve muscle, and engage in resistance training to burn fat while retaining lean mass.

Can I have too low a body fat percentage?

Yes. Dropping below essential fat levels can cause hormonal collapse, heart arrhythmias, bone loss, and reproductive issues (amenorrhea) in women.

What is the best way to measure body composition?

A DEXA (Dual-Energy X-ray Absorptiometry) scan is the clinical gold standard, tracking fat, bone density, and muscle mass by body segment.

health calculator

Body Fat Calculator

Estimate your body fat percentage using common measurements like waist, neck, and height for a quick, accurate fitness assessment.

The US Navy method estimates body fat percentage from height and circumference measurements — neck and waist for men, plus hips for women — rather than from weight. Typical healthy ranges are 8–19% for men and 21–32% for women. Circumference methods carry roughly ±3–4 percentage points of error against DEXA scanning.

Formula Verified by Dr. Sarah Jenkins, PhD

Quick actions: Save inputs, view saved runs, print, share, or export results

Saved Runs

Inputs

Mode

Sex

Heightin

Weightlbs

Waistin

Neckin

Results

Body Fat %

15.5%

CategoryFitness

Fat Mass27.9 lbs

Lean Body Mass152.1 lbs

Tip

Save this page to re-check your body fat percentage, compare against Army standards, or track your composition changes over time.

Formula

U.S. Navy body fat formulas

Men: 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76. Women: 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387.

All measurements are in inches. Body fat mass = weight × (body fat % ÷ 100). Lean body mass = weight − body fat mass.

Step by step

How the calculation works

1Choose Calculate Body Fat % or Track Changes mode.
2Calculate Body Fat %: enter your sex, height, weight, and circumference measurements to get your body fat %, category, fat mass, and lean mass.
3Track Changes: enter a starting and a current set of measurements to see how your body fat %, fat mass, and lean mass changed over time.
4All results use the U.S. Navy circumference method, which carries a typical margin of error of about 3-5%.

Related guides

Learn more about this calculation

Guide

Body Fat Percentage: How to Measure and What the Numbers Mean

Understand body fat percentage, how the US Navy method works, where smart scales and DEXA differ, and how to interpret results carefully.

Guide

BMI Calculation Guide: Formula, Ranges, and Limits

Calculate adult BMI by hand, understand the standard ranges, and learn why BMI is a screening measure rather than a diagnosis.

BMI

BMI Calculator

Calculate your Body Mass Index and see your healthy weight range from height and weight.

Metabolism

BMR Calculator

Estimate your basal metabolic rate and daily calorie needs at rest.

Calories

Calorie Calculator

Estimate your daily calorie needs for weight loss, maintenance, or muscle gain.

Ideal Weight

Ideal Weight Calculator

Find your ideal weight range based on height, sex, and body frame.

health calculator

Body Fat Calculator

Estimate your body fat percentage using common measurements like waist, neck, and height for a quick, accurate fitness assessment.

Formula Verified by Dr. Sarah Jenkins, PhD

Quick actions: Save inputs, view saved runs, print, share, or export results

Saved Runs

Inputs

Mode

Sex

Heightin

Weightlbs

Waistin

Neckin

Results

Body Fat %

15.5%

CategoryFitness

Fat Mass27.9 lbs

Lean Body Mass152.1 lbs

Tip

Save this page to re-check your body fat percentage, compare against Army standards, or track your composition changes over time.

Summary

Key output metrics

Body Fat %

15.5%

Category: Fitness.

Body composition split

The estimated breakdown of your total body weight between fat mass and lean body mass.

Fat Mass (lbs)28

Lean Mass (lbs)152

D3 visualization

Your result vs. ACE category thresholds

Compare your estimated body fat against the top of each ACE category for your sex.

Guide

How to understand and use this calculator

Quick Answer

What is body fat percentage? Body fat percentage is the proportion of your total body weight that is made up of fat tissue.

The key numbers:

Essential fat: 2-5% (men), 10-13% (women)
Athletes: 6-13% (men), 14-20% (women)
Fitness: 14-17% (men), 21-24% (women)
Average: 18-24% (men), 25-31% (women)
Obese: 25%+ (men), 32%+ (women)

Example: A 35-year-old woman with 28% body fat is in the "Average" category. A 30-year-old man with 15% body fat is in the "Fitness" category.

Why it matters: body fat percentage is a better health indicator than BMI alone because it distinguishes between fat and muscle.

Use the Body Fat Percentage Calculator

To use the calculator above: choose "Calculate Body Fat %" or "Track Changes" mode, select your sex, then enter your height, weight, and circumference measurements (waist and neck for men; waist, neck, and hip for women).

Example Input (Male): Age 30, Height 5'10" (70 in), Weight 180 lbs, Waist 34 in, Neck 16 in.

Output: Body Fat % = 15.5% • Category = Fitness • Body Fat Mass = 27.9 lbs • Lean Body Mass = 152.1 lbs

Example Input (Female): Age 35, Height 5'5" (65 in), Weight 150 lbs, Waist 30 in, Neck 13 in, Hip 40 in.

Output: Body Fat % = 31.1% • Category = Obese (just over the Average/Obese boundary at 31%) • Body Fat Mass = 46.6 lbs • Lean Body Mass = 103.4 lbs

Want your daily calorie target to match your goals? Pair this result with the Calorie Calculator or check your resting metabolism with the BMR Calculator.

What is Body Fat?

Body fat (adipose tissue) is the fat tissue in your body. It serves several important functions: energy storage, insulation, protection of internal organs, and hormone production.

Two types of body fat:

Essential Fat — the minimum fat needed for health; supports life and reproductive functions.
Storage Fat — additional accumulated fat that protects organs and provides an energy reserve.

Important: women naturally have more essential fat than men because of childbearing and hormonal functions.

What is Body Fat Percentage?

Body fat percentage is the proportion of your total body weight that is made up of fat tissue.

The formula: Body Fat % = (Body Fat Mass ÷ Total Body Weight) × 100

Example: Total weight = 180 lbs, Body fat mass = 27.9 lbs. Body fat % = (27.9 ÷ 180) × 100 = 15.5%

Why it's different from BMI: BMI only uses weight and height, while body fat percentage distinguishes between fat and muscle. Two people with the same BMI can have very different body fat percentages — a bodybuilder and an office worker might both have a BMI of 28, but the bodybuilder could have 10-12% body fat while the office worker has 30-35%. BMI can't tell the difference; body fat percentage can.

Why Does Body Fat Percentage Matter?

Benefits of healthy body fat: lower risk of heart disease, diabetes, and stroke; more efficient energy metabolism; reduced risk of sleep apnea; better athletic performance; and reduced mortality risk.

Risks of high body fat: higher blood pressure and cholesterol, strong correlation with type 2 diabetes, extra strain on joints, fat deposits contributing to sleep apnea, and disrupted hormone production.

Risks of too low body fat: hormonal disruption (especially missed periods in women), weakened immune system, higher risk of bone fractures, fatigue, and reduced organ protection.

How to Measure Body Fat — The U.S. Navy Method

The U.S. Navy method is one of the most accurate non-invasive ways to measure body fat. It uses circumference measurements, so all you need is a flexible measuring tape and a mirror for correct placement.

For Men: measure height (floor to top of head), weight (in the morning, before breakfast), neck (just below the Adam's apple, tape angled slightly downward), and waist (horizontally at the level of the navel).

For Women: measure height and weight the same way, plus neck (below the Adam's apple), waist (at the narrowest part of the waist), and hips (around the widest part, tape horizontal).

Pro tips for accurate measurements: measure in the morning before eating or drinking, stand straight and relaxed, don't suck in your stomach, keep the tape snug but not compressing the skin, and take 2-3 measurements and average them.

How to Calculate Body Fat Percentage — Step by Step

The U.S. Navy method uses these formulas:

For Men: Body Fat % = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76

For Women: Body Fat % = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387

All measurements are in inches.

Step-by-step example (Male): Waist = 34 in, Neck = 16 in, Height = 70 in.

Step 1: waist − neck = 34 − 16 = 18. log₁₀(18) = 1.2553.

Step 2: 86.010 × 1.2553 = 107.97.

Step 3: log₁₀(70) = 1.8451. 70.041 × 1.8451 = 129.23.

Step 4: Body Fat % = 107.97 − 129.23 + 36.76 = 15.5%

Note: our calculator handles all the math for you automatically.

Body Fat Percentage Categories (ACE Chart)

The American Council on Exercise (ACE) provides these categories:

Essential Fat: 10-13% (women), 2-5% (men) — the minimum healthy level, typical of athletes and bodybuilders.

Athletes: 14-20% (women), 6-13% (men) — excellent shape with low body fat.

Fitness: 21-24% (women), 14-17% (men) — good shape with healthy body fat.

Average: 25-31% (women), 18-24% (men) — within the normal, healthy range.

Obese: 32%+ (women), 25%+ (men) — may be at increased health risk.

Body Fat Percentage Chart — What's Normal?

Age-adjusted ranges for women: 20-29: Excellent 16-21%, Good 22-24%, Average 25-30%, Above Average 31-35%. 30-39: Excellent 17-22%, Good 23-25%, Average 26-31%, Above Average 32-36%. 40-49: Excellent 18-23%, Good 24-26%, Average 27-32%, Above Average 33-37%. 50-59: Excellent 19-24%, Good 25-27%, Average 28-33%, Above Average 34-38%. 60+: Excellent 20-25%, Good 26-28%, Average 29-34%, Above Average 35-39%.

Age-adjusted ranges for men: 20-29: Excellent 8-13%, Good 14-16%, Average 17-21%, Above Average 22-25%. 30-39: Excellent 9-14%, Good 15-17%, Average 18-22%, Above Average 23-26%. 40-49: Excellent 10-15%, Good 16-18%, Average 19-23%, Above Average 24-27%. 50-59: Excellent 11-16%, Good 17-19%, Average 20-24%, Above Average 25-28%. 60+: Excellent 12-17%, Good 18-20%, Average 21-25%, Above Average 26-29%.

How to Use This as an Army Body Fat Calculator

The army body fat percentage calculator uses the U.S. Navy method, which is also used by the U.S. Army.

Army maximum body fat standards: Male 17-20 = 20%, Male 21-27 = 22%, Male 28-39 = 24%, Male 40+ = 26%. Female 17-20 = 30%, Female 21-27 = 32%, Female 28-39 = 34%, Female 40+ = 36%.

How to use: calculate your body fat percentage using the U.S. Navy method above, compare it to the Army standard for your age and sex, and if you're above the limit you may need to lose fat to meet military standards.

Alternative Methods of Measuring Body Fat

U.S. Navy Method (circumference measurements) — Good accuracy, free. This calculator.

Skinfold Calipers (pinch skin at multiple sites) — Good accuracy with practice, low cost.

DXA Scan (X-ray based body composition) — Excellent accuracy, high cost.

BIA / Bioelectrical Impedance (measures electrical resistance) — Fair accuracy, low-medium cost.

Underwater Weighing (submerge body in water) — Excellent accuracy, high cost.

BOD POD (air displacement) — Excellent accuracy, high cost.

BMI Estimation (height and weight only) — Poor accuracy for body composition, free.

Recommendations: for the best free method, use the U.S. Navy Method above. For the best affordable method, use skinfold calipers with practice. For the most accurate result, get a DXA scan at a medical facility.

How to Reduce Body Fat

1. Focus on nutrition. Eat more lean protein and vegetables, choose whole grains, include healthy fats, and drink plenty of water — while avoiding processed foods, cutting back on sugar and refined carbs, limiting saturated fats, and skipping sugary drinks. Use the Calorie Calculator to find a sustainable deficit.

2. Exercise regularly. Cardio 3-5 times per week (walking, running, cycling), strength training 2-3 times per week (weight lifting, bodyweight exercises), and HIIT 2-3 times per week (sprints, circuit training).

3. Lifestyle changes. Sleep 7-9 hours per night, manage stress, stay consistent since fat loss takes time, track your progress weekly, and set realistic goals of 1-2 lbs per week.

4. Realistic fat loss goals: about 1-3% body fat loss per month, 0.5-1% per week, and 10-20% per year.

Important: fat loss should be gradual and sustainable — quick fixes don't work. Once you have a target weight in mind, the Ideal Weight Calculator can help you set a realistic healthy-weight range.

Common Body Fat Mistakes

Confusing weight loss with fat loss. Mistake: assuming weight loss = fat loss. Fix: some weight loss is water or muscle, not fat.
Measuring at the wrong time. Mistake: measuring after eating or exercising. Fix: measure in the morning, before eating.
Using the wrong measurement spots. Mistake: measuring in the wrong location. Fix: follow the U.S. Navy method exactly.
Pulling the tape too tight. Mistake: compressing the skin. Fix: the tape should be snug, not tight.
Not measuring consistently. Mistake: measuring at different times of day. Fix: always measure at the same time and conditions.
Ignoring the body fat category. Mistake: only focusing on the number, not the category. Fix: understand where you fall in the categories.
Over-focusing on body fat percentage. Mistake: obsessing over a single number. Fix: consider overall health, fitness, and well-being.
Using BMI as the only measure. Mistake: relying only on BMI. Fix: use body fat percentage for better insight — check both with the BMI Calculator.

What This Calculator Can and Cannot Do

This calculator can help with: estimating body fat percentage, tracking changes over time, identifying your body fat category, comparing to health standards, setting fitness goals, military body fat compliance, and general health risk awareness.

This calculator cannot do: replace a professional medical assessment, provide 100% accuracy (all circumference-based estimates carry roughly 3-5% error), account for individual body-shape variations, diagnose health conditions, replace a doctor's visit, or measure visceral fat directly.

Final Summary

A body fat percentage calculator is essential for anyone serious about their health and fitness. Unlike BMI, body fat percentage tells you the actual composition of your body — distinguishing between fat and muscle.

Remember the key ACE categories: Essential 10-13% (women) / 2-5% (men) • Athletic 14-20% (women) / 6-13% (men) • Fitness 21-24% (women) / 14-17% (men) • Average 25-31% (women) / 18-24% (men) • Obese 32%+ (women) / 25%+ (men).

Start now — just enter your measurements above and get your body fat percentage, category, fat mass, and lean mass, completely free. If you want to track progress over months, switch to "Track Changes" mode above.

Related concepts

Body Fat Percentage

The proportion of total body weight made up of fat tissue, calculated as (Body Fat Mass ÷ Total Body Weight) × 100.

U.S. Navy Circumference Method

A non-invasive body fat estimation method using height, neck, waist (and hip for women) measurements.

Lean Body Mass

Total body weight minus fat mass — includes muscle, bone, organs, and water.

Essential Fat

The minimum fat needed for basic physiological function: 2-5% for men and 10-13% for women.

Frequently Asked Questions

What is a body fat percentage calculator?+

A body fat percentage calculator estimates the proportion of your total body weight that is made up of fat tissue using measurements like height, weight, and circumference.

What is my body fat percentage?+

Your body fat percentage is your fat tissue mass divided by your total body weight. Use the calculator above with your waist, neck, height, and weight (plus hip for women) to get your estimate.

What is a healthy body fat percentage?+

For men: 18-24% is average, 14-17% is fitness, 6-13% is athletic. For women: 25-31% is average, 21-24% is fitness, 14-20% is athletic.

How do I work out fat percentage?+

You can work out fat percentage using the U.S. Navy method with waist, neck, and hip measurements, or use the calculator above to do the math automatically.

What is the body fat percentage chart?+

A body fat percentage chart shows healthy ranges by age and gender. It includes categories: Essential, Athletic, Fitness, Average, and Obese.

What is the army body fat percentage calculator?+

The army body fat percentage calculator uses the U.S. Navy method to determine if you meet military body fat standards, which vary by age and sex.

What is the difference between body fat and BMI?+

BMI uses only height and weight. Body fat percentage measures actual fat tissue, making it more accurate for assessing body composition and health.

How accurate is the U.S. Navy method?+

The U.S. Navy method is one of the most accurate non-invasive methods, with a typical error of about 3-5% compared to lab methods like DXA.

How often should I measure my body fat?+

Measure once per week or once every two weeks to track progress without becoming obsessive about a single number.

What is essential body fat?+

Essential fat is the minimum fat needed for health. For men it's 2-5%, for women it's 10-13%, due to reproductive and hormonal functions.

Can I reduce body fat without losing muscle?+

Yes — through balanced nutrition, strength training, and a gradual, moderate calorie deficit rather than an aggressive one.

Is this body fat percentage calculator free?+

Yes — completely free with no registration required.

Formula

U.S. Navy body fat formulas

Men: 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76. Women: 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387.

All measurements are in inches. Body fat mass = weight × (body fat % ÷ 100). Lean body mass = weight − body fat mass.

Step by step

How the calculation works

1Choose Calculate Body Fat % or Track Changes mode.
2Calculate Body Fat %: enter your sex, height, weight, and circumference measurements to get your body fat %, category, fat mass, and lean mass.
3Track Changes: enter a starting and a current set of measurements to see how your body fat %, fat mass, and lean mass changed over time.
4All results use the U.S. Navy circumference method, which carries a typical margin of error of about 3-5%.

Related guides

Learn more about this calculation

Guide

Body Fat Calculator

Inputs

Results

U.S. Navy body fat formulas

How the calculation works

Learn more about this calculation

Body Fat Percentage: How to Measure and What the Numbers Mean

BMI Calculation Guide: Formula, Ranges, and Limits

BMI Calculator

BMR Calculator

Calorie Calculator

Ideal Weight Calculator

Sources & methodology

Body Fat Calculator

Inputs

Results

Key output metrics

Body composition split

Your result vs. ACE category thresholds

How to understand and use this calculator

Quick Answer

Use the Body Fat Percentage Calculator

What is Body Fat?

What is Body Fat Percentage?

Why Does Body Fat Percentage Matter?

How to Measure Body Fat — The U.S. Navy Method

How to Calculate Body Fat Percentage — Step by Step

Body Fat Percentage Categories (ACE Chart)

Body Fat Percentage Chart — What's Normal?

How to Use This as an Army Body Fat Calculator

Alternative Methods of Measuring Body Fat

How to Reduce Body Fat

Common Body Fat Mistakes

What This Calculator Can and Cannot Do

Final Summary

Related concepts

Frequently Asked Questions

U.S. Navy body fat formulas

How the calculation works

Learn more about this calculation

Body Fat Percentage: How to Measure and What the Numbers Mean

BMI Calculation Guide: Formula, Ranges, and Limits

BMI Calculator

BMR Calculator

Calorie Calculator

Ideal Weight Calculator

Sources & methodology

Key output metrics

Body composition split

Your result vs. ACE category thresholds

How to understand and use this calculator

Quick Answer

Use the Body Fat Percentage Calculator

What is Body Fat?

What is Body Fat Percentage?

Why Does Body Fat Percentage Matter?

How to Measure Body Fat — The U.S. Navy Method

How to Calculate Body Fat Percentage — Step by Step

Body Fat Percentage Categories (ACE Chart)

Body Fat Percentage Chart — What's Normal?

How to Use This as an Army Body Fat Calculator

Alternative Methods of Measuring Body Fat

How to Reduce Body Fat

Common Body Fat Mistakes

What This Calculator Can and Cannot Do

Final Summary

Related concepts

Frequently Asked Questions