Body Fat Calculator
Estimate your body fat percentage, fat mass, and lean mass using proven formulas — US Navy method and BMI-based calculation. Supports US, Metric, and Stone units.
Categories:
💙 Essential Fat
🏆 Athlete
✅ Fitness
⚠️ Average
❌ Obese
Body Fat Calculator
Navy formula + BMI method
lb
Measurements (inches)
💡 Measure at the narrowest point for neck and waist. Females: measure hip at widest point.
in
in
💪
Enter Your Measurements
Your body fat percentage, fat mass, and lean mass will appear here instantly.
Medical Disclaimer: This calculator provides estimates only. Body fat measurements can vary based on hydration, measurement technique, and individual body composition. Always consult a healthcare professional for medical advice. Do not use results for diagnostic purposes.
How Body Fat is Calculated
Our body fat calculator uses two proven methods: the U.S. Navy method (tape measure-based) and BMI-based estimation. The Navy method uses circumference measurements and is widely used by military health programs. BMI-based formulas convert your weight-to-height ratio into an estimated fat percentage. Together, they provide a reliable estimate without expensive equipment. For overall weight health, also check our BMI calculator and ideal weight calculator.
📐 Calculation Methods Used
🔵 U.S. Navy Circumference Method
Uses waist, neck, and hip (females) measurements with height. Developed for US military fitness assessments. Requires a tape measure.
Male: 86.010×log(waist−neck) − 70.041×log(height) + 36.76
Female: 163.205×log(waist+hip−neck) − 97.684×log(height) − 78.387
✅ Accuracy: ±3–4%
🟢 BMI-Based Estimation
Converts Body Mass Index to estimated body fat percentage using age and sex factors. Quick and accessible without measurements.
Male: (1.20 × BMI) + (0.23 × age) − 16.2
Female: (1.20 × BMI) + (0.23 × age) − 5.4
⚠️ Accuracy: ±5–6%
📊 Body Fat Categories (ACE)
- Essential fat — Men 2–5%, Women 10–13%: Minimum needed for survival
- Athlete — Men 6–13%, Women 14–20%: Competitive sports level
- Fitness — Men 14–17%, Women 21–24%: Above average health
- Average — Men 18–24%, Women 25–31%: Acceptable health range
- Obese — Men 25%+, Women 32%+: Elevated health risk
💡 How to Reduce Body Fat
- Calorie deficit: 500 cal/day below TDEE = ~1 lb fat loss/week
- Strength training: Preserves lean mass while losing fat
- Cardio: HIIT is efficient for fat burning
- Protein: 0.7–1g/lb body weight to protect muscle
- Sleep: 7–9 hours — poor sleep increases fat storage
- Stress: High cortisol promotes visceral fat accumulation
Track calories with our calorie calculator.
⚖️ Body Fat vs BMI
BMI measures weight relative to height — it doesn't account for muscle vs fat. A muscular athlete can have a high BMI but low body fat.
Body fat % directly measures the proportion of fat tissue — a much better indicator of health risk.
Use both together for a complete picture. Check our BMI calculator alongside this tool.
📏 How to Measure Correctly
- Neck: Measure just below the larynx (Adam's apple), perpendicular to neck axis
- Waist: At the narrowest point, typically just above the navel
- Hip (females): At the widest point around the buttocks
- Measure in the morning before eating
- Use a flexible tape measure, not a ruler
- Take 2–3 readings and use the average
Frequently Asked Questions
According to the American Council on Exercise (ACE), healthy body fat ranges are: Men — 14–17% (fitness), 18–24% (average). Women — 21–24% (fitness), 25–31% (average). Athletes are lower: 6–13% for men, 14–20% for women. These ranges vary slightly with age — older adults naturally carry slightly more fat. Use our body fat calculator to see your personalized ideal range.
The US Navy circumference method has an accuracy of approximately ±3–4% compared to DEXA scans (the gold standard). It's one of the most practical and reliable methods available without professional equipment. Accuracy depends on correct measurement technique — measure consistently and take the average of multiple readings.
Fat mass is the total weight of body fat — both essential fat and storage fat. Lean mass (also called fat-free mass) includes everything else: muscles, bones, organs, water, and connective tissue. Most people focus on losing fat mass while preserving or building lean mass. Strength training and adequate protein intake help protect lean mass during weight loss.
Women naturally have higher essential fat percentages — approximately 10–13% compared to 2–5% in men — because of reproductive hormones and physiological needs. Women's bodies store more fat in the hips, thighs, and breasts for hormonal regulation and pregnancy support. This is normal and healthy. A woman at 22% body fat is in the "fitness" range, while a man at the same percentage would be in the "average" category.
Yes — this is called "body recomposition." By combining strength training with adequate protein intake and a slight calorie deficit (or maintenance), you can lose fat while gaining muscle simultaneously. The scale may not move much, but your body fat percentage drops. This is why body fat percentage is more meaningful than scale weight alone. Track progress with our body fat calculator rather than just the scale.