Body Fat Calculator
Free Body Fat Percentage Calculator. Calculate Your Body Fat, Fat Mass, and Lean Body Mass Using the Navy Method.
Use our free body fat calculator to estimate your body fat percentage using the Navy Method - a measurement-based formula that provides more detailed body composition insights than BMI alone. Enter your height, weight, and body circumference measurements to receive your personalized body fat percentage, total fat mass, and lean body mass. Our calculator works for both men and women, with imperial (pounds/inches) and metric (kilograms/centimeters) options available for accurate results.
*Scroll down for detailed instructions on how to achieve accurate measurements.
HEALTH CALCS
Input height
ft
in
Input weight
lb
Input age
lb
yr
Input gender
Input neck circumference
in
Input waist circumference
in
Input hip circumference
in
Body Fat Percentage
Body Fat Percentage
Total Body Fat Mass
Total Body Fat Mass
Total Lean Body Mass
Total Lean Body Mass
This input applies only to females. Males, please leave this blank.
This input applies only to females. Males, please leave this blank.
This input applies only to females. Males, please leave this blank.
This input applies only to females. Males, please leave this blank.
Discover More About Body Fat Below
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What is Body Fat Percentage?
Body fat percentage is the amount of fat in your body compared to everything else—your muscles, bones, organs, and water. If you weigh 150 pounds and 30 pounds of that is fat, your body fat percentage is 20%. This measurement shows you what your body is actually made of, not just how much you weigh.
Your body has two main types of fat. Essential fat is the fat your body needs to function properly—it helps with hormone production, protects your organs, and keeps you healthy. Storage fat is the extra fat your body keeps for energy. Everyone needs both types of fat, though the amount varies between men and women for biological reasons.
Body fat percentage gives you more useful information than just stepping on a scale or checking your BMI. Two people can weigh exactly the same but look completely different based on how much muscle versus fat they have. Understanding your body fat percentage helps you see the real picture of your body composition beyond what the number on the scale shows.
What's considered a good body fat percentage varies from person to person based on age, gender, and individual health. Both having too little and too much body fat can affect your health, which is why body fat percentage is useful for understanding your overall wellness. Our calculator above can help you estimate your body fat percentage using a simple measurement-based method.
The Purpose of a Body Fat Calculator
A body fat calculator estimates your body fat percentage using measurements of your body's circumferences along with your height, weight, age, and gender. Our calculator uses the Navy Method, a formula that research suggests provides reasonable estimates of body fat percentage for many people. This gives you a way to estimate your body composition without special equipment or appointments.
The main purpose of a body fat calculator is to help you understand approximately how much of your body weight is fat versus lean mass like muscle and bone. This information can be useful when thinking about your health, tracking changes over time, or working with a healthcare provider on wellness goals. A body fat calculator gives you a starting point for understanding your body composition that weight or BMI measurements alone cannot provide.
Our calculator accounts for the biological differences between men and women, as well as how factors like age and body size influence body fat percentage. Results are estimates based on your measurements, and individual body fat percentages can vary. Your body fat percentage is just one of many indicators, and any questions about your results or health goals should be discussed with a healthcare provider.
How to Measure for Our Body Fat Calculator
Our body fat calculator uses the Navy Method, which requires three simple circumference measurements that you can take at home with a measuring tape. Accurate measurements are important for getting reliable results, so taking your time and following the instructions carefully will help ensure better estimates. All measurements should be taken while standing upright in a relaxed position, and the tape should be snug but not tight enough to compress your skin.
How to Measure Neck Circumference
Wrap a measuring tape gently around your neck just below your Adam's apple (larynx), keeping the tape level all the way around. The tape should meet at the front of your neck to complete the circle. Be sure to not hold it too tight. Stand straight with your head level and keep your neck relaxed in a natural position. This number will be your input neck circumference in inches.
How to Measure Waist Circumference
Wrap a tape measure completely around your waist to form a circle. For men, measure at belly button level. For women, measure at the narrowest part of your waist (usually above your belly button). Keep your stomach relaxed and breathe normally—the tape should meet back at the front where you started to get your input waist circumference in inches.
How to Measure Hip Circumference (Women Only)
Wrap a measuring tape around the widest part of your hips and buttocks, keeping the tape level and parallel to the floor. Stand with your feet together and let the tape meet at the front to complete the circle. This measurement is only needed for women. This is your input for waist circumference in inches.
For the most accurate results, use a flexible measuring tape (like a cloth or soft tape measure) rather than a rigid ruler. Take each measurement 2-3 times to ensure consistency, and use the average if your measurements vary slightly. Measurements in either inches or centimeters work with our calculator—just make sure to use the same unit system for all your inputs. If you're tracking body fat percentage over time, try to take measurements at the same time of day and under similar conditions for better comparison.
The Body Fat Formula
The Navy Method
The Navy Method is a measurement-based formula developed by the U.S. Navy to estimate body fat percentage using body circumference measurements. This method was created as a practical way to assess body composition without specialized equipment, and research suggests it can provide reasonable estimates for many individuals. Our calculator uses this formula because it's one of the most accessible and widely studied approaches for estimating body fat percentage.
The Navy Method Formulas
For Women:
Body Fat % = 86.010 × log₁₀(waist - neck) - 70.041 × log₁₀(height) + 36.76
For Men:
Body Fat % = 163.205 × log₁₀(waist + hip - neck) - 97.684 × log₁₀(height) - 78.387
What the Equation Calculates
The Navy Method formula uses your body measurements to estimate what percentage of your total weight is fat tissue. The equation considers your neck, waist, and hip circumferences (for women) along with your height to calculate an estimated body fat percentage. These measurements help account for how your body stores fat and how body composition typically varies between individuals.
How the Formula Works
The formula applies different calculations for men and women because body fat distribution patterns differ between genders. For men, the equation uses neck and waist measurements to estimate body fat. For women, the equation includes hip measurements in addition to neck and waist, since women typically store more fat in the hip and thigh areas. The formula uses logarithmic calculations to process these measurements along with your height to produce a body fat percentage estimate.
Why Measurements Matter
Body circumference measurements provide information about fat distribution that weight and height alone cannot capture. The neck measurement helps indicate lean mass, while waist measurements reflect abdominal fat storage. For women, hip measurements account for lower body fat storage patterns. Together, these measurements allow the formula to estimate body composition more accurately than methods that rely only on weight and height, such as BMI.
How to Calculate Your Body Fat Percentage
Calculating your body fat percentage manually involves using the Navy Method formula with your body measurements. While our calculator above handles this instantly, understanding the calculation can help you see how your measurements work together to estimate body composition.
01
Step One
Apply the Navy Method Formula
Formula for Women:
Body Fat % = 163.205 × log₁₀(waist + hip - neck) - 97.684 × log₁₀(height) - 78.387
Formula for Men:
Body Fat % = 86.010 × log₁₀(waist - neck) - 70.041 × log₁₀(height) + 36.76
Measurements must be in inches. If using metric, convert first:
Centimeters ÷ 2.54 = inches
Example: 32-year-old woman, 5'5", 150 lbs
Measurements: 13" neck, 28" waist, 38" hips
Convert height: (5 × 12) + 5 = 65 inches
Body Fat % = 163.205 × log₁₀(28 + 38 - 13) - 97.684 × log₁₀(65) - 78.387 = 25.9%
02
Step Two
Calculate Fat Mass and Lean Mass
Once you have your body fat percentage, you can calculate how much of your weight is fat versus lean mass:
Fat Mass: 150 lbs × 0.259 = 38.9 lbs
Lean Body Mass: 150 lbs - 38.9 lbs = 111.1 lbs
Instead of calculating manually, our free body fat calculator provides instant results in either imperial or metric units. Simply enter your measurements and receive your estimated body fat percentage, total fat mass, and lean body mass in seconds. Once you know your lean body mass, you can use our TDEE Calculator to estimate your total daily calorie needs, as muscle tissue burns more calories at rest than fat tissue and plays a key role in determining your energy expenditure.
Body Fat Percentage vs BMI
Understanding the Difference
Body Mass Index (BMI) and body fat percentage are both measurements used to assess body composition, but they provide different types of information. BMI calculates a number based solely on your height and weight, while body fat percentage estimates the actual proportion of fat in your body compared to muscle, bone, and other tissues. Understanding the difference between these two measurements can help you get a more complete picture of your body composition.
BMI is a simple screening tool that categorizes you as underweight, normal weight, overweight, or obese based on a height-to-weight ratio. However, BMI cannot distinguish between fat mass and lean mass, which means it may not accurately reflect your body composition. For example, a muscular athlete and someone with higher body fat could have the same BMI despite having very different body compositions and health profiles.
Body fat percentage provides more detailed information because it actually estimates how much of your weight comes from fat tissue versus lean mass like muscle and bone. Two people can have the same BMI but dramatically different body fat percentages depending on their muscle mass. Someone with more muscle might have a higher BMI that falls into the "overweight" category, even though their body fat percentage indicates they're healthy and fit.
Both measurements have value as health assessment tools, but body fat percentage may give you more useful information about your actual body composition. BMI is quick and easy to calculate with just height and weight, while body fat percentage requires additional measurements but provides deeper insight. Many health professionals consider both measurements alongside other health indicators for a more complete assessment.
Our body fat calculator above uses the Navy Method to estimate your body composition, and you can use our BMI Calculator to see how your BMI compares. Neither measurement tells the whole story on its own, but together they can provide a more comprehensive understanding of your body composition and help guide conversations with healthcare providers about your health.
Body Fat Percentage for Women and Men
Body fat percentage differs significantly between women and men due to biological and hormonal differences. Women naturally have and require higher body fat percentages than men to support reproductive functions, hormone production, and overall health. These differences are part of normal human physiology and reflect how each body is designed to function optimally.
Essential body fat—the minimum amount needed for basic physiological functions—ranges from 10-13% for women compared to 2-5% for men. Women need this additional essential fat to support menstruation, pregnancy, breastfeeding, and hormone balance. This extra fat isn't excess or unhealthy; it's a necessary part of female biology that protects reproductive health and enables the body to function properly throughout different life stages.
Beyond essential fat levels, women and men also tend to store fat in different areas of the body. Women typically store more fat in the hips, thighs, and buttocks due to estrogen's influence, which is a normal and healthy fat distribution pattern. Men generally store more fat in the abdominal area due to testosterone patterns. These distribution differences are influenced by hormones and serve different biological purposes for each gender.
The difference in body fat percentages between men and women also relates to muscle mass. Men typically have higher muscle mass relative to their total body weight, which contributes to lower overall body fat percentages. Women's bodies maintain higher fat percentages alongside muscle mass to support their unique biological needs.
Understanding these natural differences helps explain why women's "healthy" body fat ranges are higher than men's. A woman at 25% body fat and a man at 15% body fat can both be equally healthy and fit—they're simply at different points on their respective healthy ranges.
Body Fat Percentage Ranges for Women and Men
Body fat percentage ranges provide general guidelines for understanding where your body composition falls relative to population averages. These ranges are meant as reference points, not strict rules, and what's considered appropriate varies based on age, genetics, activity level, and individual health circumstances. Both men and women can be healthy at different points within these ranges, and your optimal body fat percentage to support the needs of your unique body is highly individualized.
Ranges for Women
Category
Body Fat Percentage
Essential Fat
10-13%
Athletes
14-20%
Fitness
21-24%
Average
25-31%
Above Average
32%+
Ranges for Men
Category
Body Fat Percentage
Essential Fat
2-5%
Athletes
6-13%
Fitness
14-17%
Average
18-24%
Above Average
25%+
Essential fat represents the minimum body fat necessary for basic physiological functions including hormone production, vitamin absorption, and organ protection. Maintaining body fat at or below essential levels can compromise health and is not recommended for sustained periods. This range is typically only seen in competitive athletes for brief periods during competition season.
The athlete and fitness categories represent body fat percentages commonly found in people who exercise regularly and maintain active lifestyles. These ranges often reflect dedicated attention to nutrition and physical activity, though genetics and individual factors also play a role. People in these ranges typically have visible muscle definition and lower body fat levels than the general population.
The average category encompasses body fat percentages that are common in the general population and can support good health when combined with other healthy lifestyle factors. Many people fall into this range while maintaining active, fulfilling lives and experiencing no health concerns.
Body fat percentage is just one of many health indicators that contribute to overall wellness. Factors like cardiovascular fitness, strength, flexibility, sleep quality, stress management, and lifestyle habits all play important roles in health outcomes. If you have questions about where your body fat percentage falls and what it means for your individual health, discussing your results with a healthcare provider can provide personalized context and guidance.
How to Reduce Body Fat Percentage
Reducing body fat percentage involves creating conditions that support fat loss while preserving or building lean muscle mass. This process typically requires a combination of nutrition adjustments, regular physical activity, and lifestyle habits that support your body's natural metabolism. Sustainable changes tend to produce better long-term results than extreme or restrictive approaches, and what works best varies from person to person.
Nutrition and Calorie Deficit
Creating a moderate calorie deficit through nutrition is one of the primary ways to support fat loss, which means consuming slightly fewer calories than your body burns each day. A moderate deficit of 250-500 calories per day can support gradual fat loss while providing enough energy for daily activities and preserving muscle mass. Including adequate protein in your diet may help support muscle preservation and satiety—research suggests that protein helps you feel fuller longer and provides the building blocks your body needs to maintain muscle tissue. Our Calorie Deficit Calculator can help you determine an appropriate calorie target based on your individual needs.
Strength Training and Muscle Preservation
Resistance training and strength exercises play an important role in reducing body fat percentage because they help preserve and build lean muscle mass while you're in a calorie deficit. Maintaining muscle is important because muscle tissue is metabolically active and supports your resting metabolism. Activities like weight lifting, resistance bands, bodyweight exercises, and cardiovascular activities such as walking, jogging, or cycling all contribute to improving body composition. Combining both strength training and cardio often produces the best results for changing body fat percentage.
Lifestyle Factors and Consistency
Lifestyle factors including sleep quality, stress management, and consistency significantly affect body fat percentage and your ability to reduce it over time. Poor sleep and chronic stress can influence hormones that affect hunger, metabolism, and fat storage patterns. Prioritizing 7-9 hours of quality sleep, managing stress through activities you enjoy, and staying consistent with your nutrition and exercise habits can support sustainable fat loss. Remember that reducing body fat percentage is a gradual process that typically takes weeks or months, and moderate approaches tend to be more sustainable than more aggressive methods.
Factors That Affect Body Fat Percentage
Your body fat percentage is influenced by multiple biological, lifestyle, and environmental factors that work together to determine your body composition. While some of these factors are within your control to modify through lifestyle changes, others are determined by genetics and natural biological processes. Understanding what affects body fat percentage can help you set realistic expectations and make informed decisions about your health and body composition goals.
Genetics and Family History
Your genetic makeup influences how your body stores and distributes fat, as well as your natural metabolic rate and body composition tendencies. You may share similar characteristics with family members due to inherited traits that affect body fat percentage.
Diet and Nutrition Patterns
Eating patterns, calorie intake, and macronutrient balance directly affect whether your body stores or uses fat for energy. Consistent calorie intake that exceeds your body's needs may lead to fat storage, while moderate calorie deficits combined with adequate protein can support fat loss while preserving muscle mass.
Hormones and Life Stages
Hormones significantly affect body fat percentage, with changes during puberty, pregnancy, menopause, and aging all influencing fat storage and distribution. Women may experience changes due to fluctuating estrogen levels, and men may see changes with declining testosterone as they age.
Physical Activity and Exercise Habits
Regular physical activity, particularly resistance training and cardio exercise, affects body fat percentage by influencing calorie expenditure and muscle mass. Strength training helps preserve or build lean muscle tissue, which can improve body composition, while consistent activity increases calories your body burns.
Stress and Cortisol Levels
Chronic stress elevates cortisol, a hormone that can influence fat storage patterns, particularly around the abdominal area, and may affect appetite regulation. Managing stress through activities like exercise, meditation, time outdoors, or hobbies you enjoy can support better hormonal balance.
Sleep Quality and Duration
Research indicates that inadequate sleep can affect hormones that regulate hunger and metabolism, potentially making it harder to maintain or reduce body fat percentage. Getting consistent, quality sleep of 7-9 hours per night may help support healthy hormone function
These factors interact in complex ways that make each person's body fat percentage unique, which is why two people following similar nutrition and exercise routines may experience different results. Understanding these influences can help you approach body composition changes with realistic expectations and patience. Focus on the factors you can control—like nutrition, activity, sleep, and stress management—while accepting that some aspects of body composition are determined by factors outside your control. If you have concerns about your body fat percentage or factors affecting it, consulting with a healthcare provider can help you understand your individual circumstances.
Related Calorie and Health Calculators
Explore Additional Body Metrics With These Related Calculators
01
TDEE Calculator
Calculate your Total Daily Energy Expenditure based on your body composition and activity level. Essential for determining your calorie needs, based on your metabolic rate and daily activity level.
02
Calorie Deficit Calc.
Determine the calorie deficit needed to reach your weight loss goals within a specific timeframe. Helps you create a sustainable plan by showing how different deficit levels affect your progress timeline.
03
BMI Calculator
Calculate your Body Mass Index to see where your weight falls within standard health ranges. Useful for comparing BMI with body fat percentage to get a more complete picture of your body composition.
Frequently Asked Questions About Body Fat Calculators
Q: How accurate are body fat calculators?
A: Body fat calculators using the Navy Method provide estimates that can be reasonably accurate for many people, though individual results may vary by several percentage points. These calculators are best used as tools for tracking changes over time rather than infallible measurements.
Q: What is the Navy Method for body fat?
A: The Navy Method is a formula developed by the U.S. Navy that estimates body fat percentage using body circumference measurements (neck, waist, and hips for women) along with height and weight. This measurement-based approach was designed as a practical way to assess body composition without specialized equipment.
Q: Can body fat percentage change?
A: Yes, body fat percentage can change through modifications to nutrition, exercise habits, and lifestyle factors over time. Changes typically occur gradually over weeks or months, with sustainable approaches involving moderate calorie deficits, strength training, and consistent healthy habits generally producing better long-term results.
Q: What is essential body fat?
A: Essential body fat is the minimum amount of fat your body needs for basic physiological functions including hormone production, vitamin absorption, and organ protection. Women require 10-13% essential fat while men need 2-5%, and maintaining body fat below these levels can compromise health and normal bodily functions.
Q: How often should I check my body fat percentage?
A: Checking body fat percentage every 4-6 weeks provides enough time to see meaningful changes while avoiding frustration from normal daily fluctuations. Body composition changes occur gradually, so measuring too frequently may not show noticeable differences and can be discouraging rather than helpful for tracking progress.
Q: Why do women have higher body fat percentages than men?
A: Women naturally have higher body fat percentages than men to support reproductive functions, hormone production, and overall health. This additional fat is biologically necessary for menstruation, pregnancy, and hormonal balance, making women's higher body fat ranges completely normal and healthy.
Q: How can I reduce my body fat percentage?
A: Reducing body fat percentage typically involves creating a moderate calorie deficit through nutrition, engaging in regular strength training to preserve muscle mass, and maintaining consistent lifestyle habits including adequate sleep and stress management.
Q: Does muscle weigh more than fat?
A: Muscle tissue is denser than fat tissue, meaning it takes up less space at the same weight. This is why two people can weigh the same but look different based on their body composition—someone with more muscle and less fat will typically appear leaner even at the same total body weight.
Q: Is body fat percentage more important than weight?
A: Body fat percentage and weight provide different types of information, and neither is definitively "more important" than the other. Body fat percentage gives you insight into body composition that weight alone cannot provide, but both measurements can be useful alongside other health indicators when assessing overall wellness.
Q: What is a good body fat percentage?
A: A "good" body fat percentage varies based on your age, gender, personal goals and individual health circumstances rather than a single universal number. For women, ranges between 21-31% and for men between 14-24% are generally considered average and can support good health.
A Note from Health Calcz
Disclaimer* - This body fat calculator provides educational information based on the Navy Method body composition estimation formula. Results are estimates for informational purposes only and should not be used for medical diagnosis, treatment decisions, or as fitness or nutrition prescriptions. Body fat calculators use population averages and standardized formulas that may not reflect individual body composition, measurement accuracy, or actual body fat percentages. Factors including muscle mass distribution, bone density, hydration levels, genetics, hormones, medical conditions, and body type affect body fat percentage in ways calculators cannot fully assess. This tool and information are not medical, fitness, or nutritional advice and don't replace consultation with qualified healthcare professionals. Body fat percentage estimates based on circumference measurements have inherent limitations and margins of error compared to clinical assessment methods. For accurate body composition analysis, personalized fitness guidance, health assessments, or concerns about your body fat calculator results, consult your doctor, registered dietitian, or certified fitness professional. If you have medical conditions, are pregnant or breastfeeding, have a history of eating disorders, are taking medications that affect body composition, or have questions about appropriate body fat levels or weight management, contact your healthcare provider before making changes to your diet or exercise routine.