Investment & Savings
Loans & Borrowing
Daily Money Tools
Wealth & Net Worth
Business Finance
Body & Weight
Nutrition & Diet
Fitness & Training
Pregnancy & Women
🐕 Dog Tools
🐈 Cat Tools
🐟 Fish & Aquarium
🦎 Other Pets
Pet Health & Costs
🎓 Academic Tools
📖 Productivity
⏰ Time & Date
🌍 Life & Travel
Pricing & Profit
Payroll & HR
Freelance & Self-Employed
💰 Finance
🏋 Health & Fitness
🐾 Pets & Animals
🎓 Lifestyle & Education
💼 Business
HomeAboutContact PrivacyTermsDisclaimer
Health & Fitness · Free Calculator

Body Fat %
Calculator

Estimate your body fat percentage using the US Navy method. See your fat mass, lean mass, and body composition category. More accurate than BMI for fitness assessment.

Your Body Composition
US Navy method estimate
Body Fat
18.5%
Category
Average
Fat Mass
13.0 kg
Lean Mass
57.0 kg
EssentialAthleteFitnessAverageAbove Avg
Body Fat Categories
CategoryBF% RangeFat at Your Weight
// Health · ShashaTools
Body Fat Calculator
Sex
Height 170 cm
120220
Weight 70 kg
30200
Waist 82 cm
50150
Measure at navel level. Relaxed, not sucked in.
Neck 37 cm
2555
Below the Adam’s apple. Keep tape level.
Hip 95 cm
60160
Widest point of hips/buttocks. Women only.
// Results
Body Fat %
18.5%
Category
Average
Fat Mass
13.0 kg (28.6 lbs)
Lean Mass
57.0 kg (125.7 lbs)
Ratio
4.4:1 lean-to-fat
18.5% body fat — Average (male)
How to Use This Calculator
Estimate body fat using the US Navy circumference method
Step 1 Take Measurements
1
Select your sex
Categories differ significantly between men and women. Women require a hip measurement in addition to waist and neck.
2
Measure your waist
At navel level for men, narrowest point for women. Stand relaxed. Use flexible tape snug against skin. Do not suck in your stomach.
3
Measure your neck
Just below the Adam’s apple. Keep tape level and horizontal. Look straight ahead. Snug but not compressing.
4
Measure hips (women)
At the widest point of your hips and buttocks. Keep tape level. This measurement is required for the female formula.
💡 Tip: Measure in the morning, before eating, same time every session. Use a mirror to keep the tape level. Take each measurement twice and average for accuracy.
Step 2 Read Results
1
Check your category
Essential → Athlete → Fitness → Average → Above Average. The gauge shows where you fall visually.
2
Review fat vs lean mass
Fat mass is total body fat in kg. Lean mass is everything else: muscle, bone, water, organs. A higher lean-to-fat ratio is healthier.
3
Compare to the table
The category table shows what your fat mass would be at each category level, helping you set realistic goals.
4
Track over time
Measure every 2-4 weeks. Body fat changes slowly. The trend matters more than any single reading.
💡 Accuracy: The US Navy method is within 1-3% of DEXA scans for most people. For higher precision, consider DEXA or hydrostatic weighing at a local clinic.
// Recommended Tools

ℹ️ Affiliate disclosure: Some links are affiliate links.

Body Fat Calipers
Affordable skinfold calipers for at-home body fat tracking.
Compare →
Smart Scales
Scales that estimate body fat via bioelectrical impedance.
Compare →
MyFitnessPal
Track nutrition to optimize body composition.
Get Started →
Measuring Tape
Flexible body measuring tape for accurate circumferences.
Shop →
// Related Calculators
⚖️
BMI Calculator
Quick weight classification by height and weight.
📊
TDEE & Macro Calculator
Calories and macros for your body composition goals.
🔥
Calorie Deficit Calculator
Find the right deficit for fat loss.
🥑
Keto Macro Calculator
Low-carb macros for body recomposition.
// Complete Guide — Updated 2026

Understanding Body Fat %:
The Complete Guide

Body fat percentage is the single most useful metric for assessing body composition. Unlike BMI, which uses only height and weight, body fat percentage tells you how much of your weight is actually fat versus muscle, bone, and organs. This guide covers how to measure it, what the numbers mean, and how to use this information to set realistic fitness goals.

The US Navy Formula

// Men
BF% = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76
86.010 × log10(82-37) - 70.041 × log10(170) + 36.76 = 18.5%
// Women
BF% = 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387

Body Fat Categories

CategoryMenWomen
Essential Fat2-5%10-13%
Athlete6-13%14-20%
Fitness14-17%21-24%
Average18-24%25-31%
Above Average25%+32%+

Real-World Scenarios

Scenario 1: Average Office Worker. James, 30, male: height 175 cm, weight 82 kg, waist 90 cm, neck 38 cm. Body fat: 22.4% — Average. Fat mass: 18.4 kg. Lean mass: 63.6 kg. To reach Fitness (17%), he needs to lose about 4.4 kg of fat while maintaining muscle. Use our Calorie Deficit Calculator to plan.

Scenario 2: Active Woman. Maria, 28, female: height 165 cm, weight 62 kg, waist 72 cm, neck 33 cm, hip 96 cm. Body fat: 24.1% — Fitness. Fat: 14.9 kg. Lean: 47.1 kg. She is in the fitness category. To maintain, use our TDEE Calculator.

Scenario 3: Competitive Athlete. David, 25, male: height 180 cm, weight 85 kg, waist 78 cm, neck 40 cm. Body fat: 12.8% — Athlete. BMI says 26.2 (overweight). Body fat says athlete. This is why body fat is more useful than BMI for fit individuals. His lean mass is 74.1 kg.

Scenario 4: Weight Loss Journey. Sarah started at 35% body fat (90 kg). After 6 months of deficit eating and resistance training, she is at 27% body fat (78 kg). She lost 12 kg total: 10.5 kg fat, only 1.5 kg lean mass. That lean preservation means her metabolism stayed strong. Use our Calories Burned Calculator to optimize her training.

💡 Key insight: The scale does not tell the whole story. Someone who starts strength training may stay the same weight for months while their body composition transforms — losing fat and gaining muscle simultaneously. Body fat percentage captures this change. The scale misses it entirely. Measure body fat, not just weight.

Measurement Tips
WhenMorning, before food
How oftenEvery 2-4 weeks
Tape tensionSnug, not tight
WaistAt navel, relaxed
Accuracy±1-3% vs DEXA
// Frequently Asked Questions
Common Questions About Body Fat
How do I calculate body fat? +
The US Navy method uses height, waist, neck (and hip for women) measurements with a logarithmic formula. More accurate than BMI for body composition.
What is a healthy body fat %? +
Men: 14-18% fitness, 18-25% average. Women: 21-25% fitness, 25-32% average. Athletes are lower. Essential minimum: men 2-6%, women 10-14%.
Is the US Navy method accurate? +
Within 1-3% of DEXA scans. More accurate than BMI. Less than DEXA or hydrostatic weighing but only needs a tape measure. Best for tracking trends.
How do I measure my waist? +
At navel level. Stand relaxed, do not suck in. Flexible tape snug against bare skin. Not compressing. Same time of day each measurement.
How do I measure my neck? +
Just below the Adam's apple. Tape level and horizontal. Look straight ahead. Snug but not tight. Critical for formula accuracy.
Lean mass vs fat mass? +
Lean = muscle, bone, organs, water. Fat = all body fat. A 70 kg person at 20% has 14 kg fat and 56 kg lean mass.
How fast can I lose body fat? +
Safely 0.5-1% per month or ~1 lb/week of fat. 500-calorie daily deficit = ~1 lb/week. Resistance training preserves muscle during fat loss.
Why is body fat better than BMI? +
BMI cannot distinguish muscle from fat. Body fat measures fat directly. A muscular person with BMI 28 and 12% BF is healthier than sedentary BMI 24 at 30% BF.
What is essential body fat? +
Minimum for physiological function: men 2-5%, women 10-13%. Below causes hormonal disruption, organ damage, immune failure. Athletes should not go below.
How often should I measure? +
Every 2-4 weeks max. Same time, same conditions. Morning before eating. Track the trend, not individual readings. Body fat changes slowly.