Body Composition Calculator

Analyze your body composition including body fat percentage, lean body mass, and muscle mass. Track your physique changes and monitor progress with accurate body composition analysis.

Body Measurements

Understanding Body Composition

Body composition refers to the proportion of fat and non-fat mass in your body. This calculator uses the U.S. Navy method, which estimates body fat percentage based on circumference measurements.

Body Fat Percentage Categories

Men

  • Essential Fat: 2-5%
  • Athletes: 6-13%
  • Fitness: 14-17%
  • Average: 18-24%
  • Obese: 25%+

Women

  • Essential Fat: 10-13%
  • Athletes: 14-20%
  • Fitness: 21-24%
  • Average: 25-31%
  • Obese: 32%+

Measurement Tips

  • Take measurements at the same time of day
  • Measure on bare skin when possible
  • Keep the tape measure level and snug but not tight
  • Take multiple measurements and use the average

How This Body Composition Calculator Works

This body composition calculator estimates your body fat percentage, lean body mass (LBM), and related metrics using the U.S. Navy method. The calculation uses neck, waist, and for females hip measurements alongside height and weight to provide a practical body composition analysis you can repeat over time.

While tools like DEXA scans, calipers, and BIA devices can provide different levels of precision, the Navy formula is an excellent balance of accuracy, consistency, and accessibility—ideal for physique tracking and performance goals.

Body Composition vs BMI

BMI (Body Mass Index) is a weight-to-height ratio that does not distinguish between fat and muscle. Body composition tells you how much of your body is fat versus lean tissue. Athletes and lifters often have a higher BMI due to greater muscle mass, so tracking body fat percentage and lean body mass is much more meaningful.

  • Body Fat %: Estimated adipose tissue proportion
  • Lean Body Mass: Everything except fat (muscle, bone, organs, water)
  • BMI: Helpful for population studies, limited for trained individuals

Improve Your Body Composition

  • Prioritize Protein: Aim for ~1.6–2.2 g/kg body weight daily
  • Lift Consistently: 2–4+ days/week of resistance training to build muscle
  • Dial Calories: Use modest deficits for fat loss; slight surplus for muscle gain
  • Monitor NEAT: Daily steps and activity support calorie balance
  • Sleep 7–9 Hours: Better recovery, appetite control, and hormone balance

For nutrition guidance, see Nutrition for Strength Athletes and try our Body Fat Calculator for complementary estimates.

Accuracy, Methods, and Best Practices

  • Measure Consistently: Same time of day, similar hydration, consistent tape placement
  • Combine Metrics: Track waist, weight, and progress photos
  • Expect Variation: Short-term fluctuations are normal—focus on weekly trends

If you need a deeper dive into training strategies that support recomposition, explore Advanced Training Techniques.

Body Composition FAQs

  • How often should I measure? Weekly or biweekly is ideal for trend analysis.
  • Is Navy method accurate? It’s reliable for tracking, but devices like DEXA may be more precise.
  • Does hydration affect results? Yes—aim for consistent measurement conditions.
  • Should I use BMI? Use BMI for general context; rely on body fat % and LBM for athletes.