Body Fat Calculator (US Navy Method)
Estimate your body fat percentage using circumference and measurement data. Uses the US Navy circumference formula.
Body Fat Calculator
Estimate your body fat percentage using circumference and measurement data.
Calculate
Example: 5'7" = 67 inches
Measure around your neck at the narrowest point
fields.waistHint
results.yourBodyFat
Body Fat Percentage Ranges
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2-5% | 10-13% |
| Athletes | 6-13% | 14-20% |
| Fitness | 14-17% | 21-24% |
| Average | 18-24% | 25-31% |
| Obese | 25%+ | 32%+ |
Understanding Body Fat Percentage
Body fat percentage is the proportion of fat mass to total body mass. Unlike BMI, which only accounts for height and weight, body fat percentage provides a more accurate picture of your health and fitness level. Two people with the same BMI can have vastly different body fat percentages depending on their muscle mass.
This calculator uses the U.S. Navy Method, which estimates body fat percentage based on circumference measurements. While not as accurate as DEXA scans or hydrostatic weighing, it provides a good approximation and is convenient for tracking changes over time.
Why Body Fat Percentage Matters
🏃 Better Than BMI
BMI doesn't distinguish between muscle and fat. A muscular athlete might have a high BMI but low body fat, while someone with little muscle could have a normal BMI but high body fat (sometimes called "skinny fat"). Body fat percentage gives you the real story about your body composition.
❤️ Health Indicator
Excess body fat, especially visceral fat around organs, increases risks for heart disease, type 2 diabetes, high blood pressure, and certain cancers. Maintaining a healthy body fat percentage reduces these risks more effectively than focusing on weight alone.
💪 Fitness Goals
Whether you're trying to lose fat, gain muscle, or improve athletic performance, tracking body fat percentage helps you monitor progress more accurately than the scale. You can lose fat while gaining muscle, which won't show up on a traditional scale but will reflect in body fat measurements.
⚖️ Essential vs. Storage Fat
Essential fat is necessary for survival (2-5% for men, 10-13% for women). Going below these levels can cause serious health problems including hormonal imbalances, loss of menstruation in women, and immune system dysfunction. Storage fat provides energy reserves and insulation.
How to Measure Accurately
Use a Flexible Tape Measure
Use a cloth or vinyl tape measure, not a rigid ruler. The tape should be snug but not compressing your skin. Keep it parallel to the floor and perpendicular to your body.
Measure at the Same Time
Take measurements first thing in the morning before eating for consistency. Body measurements can vary throughout the day due to food intake, hydration, and activity level.
Neck: Below the Adam's Apple
Measure around your neck at the narrowest point, typically just below your Adam's apple (laryngeal prominence). Stand tall and look straight ahead, not down.
Waist: At the Navel
For men and women, measure around your natural waistline at the level of your belly button. Don't suck in your stomach—breathe normally and measure at the end of a normal exhale.
Hips: Widest Point (Women)
Measure around the widest part of your hips and buttocks. Stand with feet together and measure while looking straight ahead to avoid leaning.
How to Reduce Body Fat Safely
Moderate Calorie Deficit
Aim for 300-500 calories below maintenance for sustainable fat loss of 0.5-1 lb per week. Extreme deficits can lead to muscle loss and metabolic slowdown.
Strength Training
Lift weights 3-4 times per week to preserve muscle mass while losing fat. Muscle burns more calories at rest than fat tissue.
Adequate Protein
Consume 0.7-1g of protein per pound of body weight daily to maintain muscle mass and increase satiety during fat loss.
Quality Sleep
Get 7-9 hours of sleep per night. Poor sleep increases cortisol and hunger hormones, making fat loss much harder.
Limitations of This Calculation
Estimation, Not Precision
The Navy Method has a margin of error of ±3-4%. For more accurate measurements, consider DEXA scans, hydrostatic weighing, or bod pod testing.
Measurement Errors
Small measurement errors (even 0.5 inches) can significantly affect the result. Use the same tape measure and measuring technique each time for consistency.
Track Trends, Not Single Measurements
Focus on the trend over weeks and months rather than day-to-day fluctuations. Take measurements weekly under the same conditions.
Frequently Asked Questions
What is a healthy body fat percentage?
For men, a healthy range is 10-20%, with athletes at 6-13% and fitness enthusiasts at 14-17%. For women, healthy is 18-28%, with athletes at 14-20% and fitness at 21-24%. Women require higher essential fat levels (10-13%) compared to men (2-5%) due to hormonal and reproductive functions. Going below essential fat levels can cause serious health problems.
How accurate is the Navy Method for calculating body fat?
The Navy Method has a margin of error of ±3-4%, making it reasonably accurate for tracking changes over time but not as precise as DEXA scans (±1-2%) or hydrostatic weighing (±2-3%). Its accuracy depends heavily on proper measurement technique. The same person measuring consistently will get better trend data than trying to achieve a perfectly accurate single measurement.
Why is my body fat percentage different from my BMI category?
BMI only considers height and weight, not body composition. A muscular person might have a high BMI (overweight/obese category) but low body fat percentage because muscle weighs more than fat. Conversely, someone with low muscle mass might have a normal BMI but high body fat percentage (sometimes called "skinny fat"). Body fat percentage gives a more accurate picture of your actual health and fitness level.
How quickly can I reduce my body fat percentage?
A safe, sustainable rate is 0.5-1% body fat loss per month (roughly 0.5-1 lb of fat per week). Faster rates often lead to muscle loss along with fat. For example, reducing from 25% to 15% body fat would take 10-20 months. The process is slower as you get leaner—losing the last 5% takes longer than the first 5% because your body protects remaining fat stores more aggressively.
Can I spot reduce fat from specific areas?
No, spot reduction is a myth. You cannot target fat loss from specific body areas through exercises like crunches for belly fat or tricep exercises for arm fat. Fat loss occurs throughout your body based on genetics, hormones, and your body's preferred fat storage patterns. However, building muscle in specific areas through targeted exercises can improve the appearance of those areas as you lose overall body fat.
Should I focus on body fat percentage or weight on the scale?
Body fat percentage is a better indicator of health and fitness than scale weight. You can gain muscle while losing fat, which might keep your weight the same or even increase it while you're getting leaner and healthier. Track both body fat percentage and scale weight, along with progress photos and how your clothes fit, for the most complete picture. If you're strength training, expect slower scale weight changes as muscle gain offsets fat loss.
Share this calculator
Related Calculators
Check out these other helpful calculators