Body Fat Calculator
Calculate your body fat percentage using the scientifically-validated US Navy method or BMI-based estimation. Get instant results with lean body mass, fat mass, and personalized health insights. Trusted by millions for accurate body composition analysis.
Quick Answer: How to Calculate Body Fat Percentage
Body fat percentage measures the proportion of fat tissue in your body. The US Navy method calculates it using height, neck, and waist circumferences (plus hips for women). Healthy ranges are 8-19% for men and 21-33% for women.
- Measure your neck circumference below the Adam's apple
- Measure your waist at navel (men) or narrowest point (women)
- Women: Measure hips at the widest point
- Enter measurements along with your height
- Get instant results with health category and recommendations
💡 Try These Examples
| Method | Body Fat % | Category | Accuracy |
|---|---|---|---|
| US Navy | — | — | ±3-4% |
| BMI-Based | — | — | ±5-8% |
| Average | — | — | — |
📊 Method Accuracy Comparison
No measurements saved yet. Use the calculator and click "Save Result" to start tracking.
🔍 People Also Ask About Body Fat
What body fat percentage is considered skinny?
For men, body fat below 8-10% is considered very lean, while for women it's below 18-20%. At these levels, muscle definition is highly visible. However, maintaining extremely low body fat can be unhealthy long-term.
Is 20% body fat good for a man?
Yes, 20% body fat is within the healthy "Average" range for men according to the American Council on Exercise. At 20%, you'll have some visible muscle definition with a softer midsection. It's associated with low health risks.
How much body fat can you lose in a month?
A safe and sustainable rate is 1-2% body fat per month, or roughly 0.5-1 pound of fat per week. This requires a moderate caloric deficit of 500-750 calories per day combined with resistance training.
Why do women have higher body fat than men?
Women naturally carry more body fat due to biological functions. Essential fat for women is 10-13% compared to 2-5% for men. This extra fat supports reproductive functions, hormone production, and breast tissue.
Does body fat percentage affect testosterone?
Yes, higher body fat increases aromatase enzyme activity, which converts testosterone to estrogen. Studies show men with obesity can have testosterone levels 25-45% lower than lean men. The optimal range is approximately 10-20% body fat.
What is skinny fat?
"Skinny fat" (medically called normal-weight obesity) describes having a normal BMI but high body fat percentage—typically above 24% for men or 32% for women. This carries similar metabolic risks as obesity.
What body fat percentage shows visible abs?
Men need approximately 10-14% body fat for visible abs, with full "six-pack" definition usually appearing below 10%. Women typically see ab definition at 16-20% body fat.
Is visceral fat more dangerous than subcutaneous fat?
Yes, visceral fat poses greater health risks. According to Harvard Medical School, it releases inflammatory cytokines and is linked to insulin resistance, type 2 diabetes, and heart disease. Waist circumference indicates risk—men over 40" and women over 35" are at increased risk.
Is body fat or BMI more important?
Body fat percentage is more informative for health assessment. BMI only considers height and weight, potentially misclassifying muscular individuals. Research shows body fat percentage better predicts cardiovascular disease and mortality risk.
Can you build muscle and lose fat simultaneously?
Yes, through body recomposition. It's most effective for beginners, those returning from a break, and those with higher body fat. Key factors: slight caloric deficit, high protein (0.8-1g/lb), strength training, and adequate sleep.
How accurate are body fat scales?
Bioelectrical impedance (BIA) scales have an accuracy of ±4-8%, making them less reliable than other methods. Results are heavily influenced by hydration, recent meals, and time of day. They're best for tracking trends over time.
What happens if body fat is too low?
Extremely low body fat (below 4-5% for men, 12-14% for women) causes: hormonal disruption, loss of menstruation in women, weakened immune system, decreased bone density, impaired brain function, and potential organ damage.
📖 What is Body Fat Percentage?
Body fat percentage is the proportion of your total body weight that consists of fat tissue, expressed as a percentage. Unlike body weight alone or BMI, body fat percentage directly measures your body composition—distinguishing between fat mass and lean mass (muscle, bone, organs, and water).
Your body contains two types of fat: essential fat and storage fat. Essential fat is necessary for life, supporting vital functions like hormone production, temperature regulation, and organ cushioning. For men, essential fat is approximately 2-5% of body weight; for women, it's 10-13% due to reproductive and hormonal requirements. Storage fat is the fat accumulated in adipose tissue beneath the skin (subcutaneous fat) and around organs (visceral fat).
According to the American Council on Exercise (ACE), healthy body fat ranges vary by gender and fitness level. For the general population, men should aim for 18-24% body fat, while women should target 25-31%. Athletes and fitness enthusiasts typically maintain lower percentages—6-13% for men and 14-20% for women.
Why Body Fat Percentage Matters
Research published in the Journal of the American Medical Association shows that body fat percentage is a better predictor of cardiovascular disease and metabolic syndrome than BMI. A 2019 study found that individuals with "normal weight obesity" (normal BMI but high body fat) had a 30% higher risk of cardiovascular mortality.
🧮 Body Fat Percentage Formulas Explained
Several scientifically-validated formulas exist for calculating body fat percentage. This calculator uses the US Navy method (circumference-based) and BMI-based estimation.
US Navy Method Formula
Developed by Hodgdon and Beckett (1984) at the Naval Health Research Center:
BF% = 86.010 × log₁₀(waist - neck) - 70.041 × log₁₀(height) + 36.76
For Women:
BF% = 163.205 × log₁₀(waist + hip - neck) - 97.684 × log₁₀(height) - 78.387
BMI-Based Formula
This formula estimates body fat from BMI, age, and gender:
For Adult Women: BF% = (1.20 × BMI) + (0.23 × Age) - 5.4
📊 Body Fat Percentage Chart by Age and Gender
Body fat percentage ranges vary by age, gender, and activity level. The following charts help you understand where your body fat percentage falls.
Body Fat Categories (American Council on Exercise)
| Category | Women | Men | Description |
|---|---|---|---|
| Essential Fat | 10-13% | 2-5% | Minimum for survival |
| Athletes | 14-20% | 6-13% | Competitive athletes |
| Fitness | 21-24% | 14-17% | Fit individuals |
| Average | 25-31% | 18-24% | Healthy population |
| Obese | 32%+ | 25%+ | Health risks |
Healthy Body Fat by Age (Harvard Health / WHO Guidelines)
| Age Range | Men (Healthy) | Women (Healthy) |
|---|---|---|
| 20-39 years | 8-19% | 21-33% |
| 40-59 years | 11-21% | 23-34% |
| 60-79 years | 13-24% | 25-36% |
📝 How to Measure Body Fat Accurately
Accurate body fat calculation depends on precise measurements. Follow these instructions for the US Navy tape measure method:
Measure Your Neck
Place the tape just below your larynx (Adam's apple), keeping it level. Look straight ahead with shoulders relaxed.
Measure Your Waist
For men: Measure at the navel. For women: Measure at the narrowest point. Stand relaxed—don't suck in your stomach.
Measure Your Hips (Women Only)
Stand with feet together. Wrap the tape around the widest point of your hips and buttocks. Keep tape level.
💡 Pro Tips for Accurate Measurements
- Take each measurement three times and use the average
- Measure in the morning before eating or drinking
- Keep the tape parallel to the floor
- Don't hold your breath during measurement
🏥 Health Implications of Body Fat Levels
Body fat percentage has significant implications for your health, affecting everything from cardiovascular function to hormonal balance.
Risks of High Body Fat
According to the World Health Organization (WHO), excess body fat is associated with:
- Cardiovascular Disease: High body fat increases LDL cholesterol and blood pressure
- Type 2 Diabetes: Excess fat causes insulin resistance
- Certain Cancers: Obesity is linked to 13 types of cancer
- Sleep Apnea: Excess neck and abdominal fat can obstruct airways
Risks of Too-Low Body Fat
- Hormonal Disruption: Low testosterone (men) / loss of menstruation (women)
- Weakened Immune System
- Decreased Bone Density
- Poor Temperature Regulation
💪 How to Reduce Body Fat Safely
Reducing body fat while preserving muscle requires a strategic approach:
Nutrition Strategy
- Moderate caloric deficit (300-500 cal/day)
- High protein (0.7-1g per pound)
- Fiber-rich vegetables for satiety
- Limit processed foods and added sugars
Exercise Approach
- Resistance training 3-4x/week
- Progressive overload
- Moderate cardio (150 min/week)
- Daily movement: 8,000-10,000 steps
Recovery & Lifestyle
- Sleep 7-9 hours
- Manage stress (controls cortisol)
- Limit alcohol
- Track progress monthly
📉 Safe Rate of Fat Loss
Aim to lose 0.5-1% of body weight per week. For body fat percentage, expect to lose 1-2% per month with consistent effort.
This body fat calculator uses the scientifically-validated US Navy circumference method developed by Hodgdon and Beckett (1984). Content reviewed for accuracy based on guidelines from the American Council on Exercise, World Health Organization, and peer-reviewed research.
Last reviewed: February 15, 2026
📚 Sources & References
- Hodgdon, J.A., & Beckett, M.B. (1984). Prediction of percent body fat for U.S. Navy men and women. Naval Health Research Center.
- American Council on Exercise. (2023). Body Fat Percentage Norms. ACE Fitness.
- World Health Organization. (2022). Obesity and Overweight Fact Sheet. WHO.
- Harvard Medical School. (2023). What is a healthy body fat percentage? Harvard Health Publishing.
- Jackson, A.S., & Pollock, M.L. (1978). Generalized equations for predicting body density. British Journal of Nutrition.
- Centers for Disease Control and Prevention. (2024). Body Mass Index: Considerations for Practitioners.
❓ Frequently Asked Questions
Healthy body fat ranges increase with age. Ages 20-39: Men 8-19%, women 21-33%. Ages 40-59: Men 11-21%, women 23-34%. Ages 60-79: Men 13-24%, women 25-36%. These ranges account for natural metabolic changes with aging.
The US Navy method has an accuracy of ±3-4% when measurements are taken correctly. While not as precise as DEXA scans (±1.5%), it's the most practical and reliable home measurement option.
Different methods use different algorithms with varying accuracy. BIA scales are affected by hydration and time of day. Pick one method and use it consistently to track trends over time.
Yes! This is called body recomposition—losing fat while gaining muscle. It requires high protein intake, resistance training, and adequate sleep. Progress shows in measurements and body fat percentage rather than scale weight.
With sustainable methods, expect to lose 1-2% body fat per month. So losing 10% body fat would take approximately 5-10 months. This rate minimizes muscle loss and prevents metabolic adaptation.
No. Body fat measurements fluctuate daily. Measure every 2-4 weeks under consistent conditions. Focus on the long-term trend over 8-12 weeks.
Women carry more body fat for biological and reproductive functions. Essential fat (10-13%) supports hormone production, pregnancy, and nursing. Women also store fat differently—primarily in hips and thighs.
Yes, studies suggest 40-70% of body fat variation is heritable. Genetics influence where you store fat, metabolism, and appetite. However, lifestyle factors have enormous impact on actual body fat levels.