Body Fat Percentage Calculator (USA)

Calculate your body fat percentage using BMI and age. This is an estimation of body fat based on the Deurenberg formula.

How to Calculate Body Fat Percentage

Body fat percentage is estimated using the Deurenberg formula:

\[\text{Body Fat \%} = (1.20 \times \text{BMI}) + (0.23 \times \text{age}) - 16.2\]
  • Formula: Body Fat % = (1.20 × BMI) + (0.23 × age) - 16.2
  • Inputs: BMI, age
  • Output: Body Fat Percentage

Body Fat Calculator

BMI

22.9

Age

30 yrs

21.2%

Body Fat %

Category

Fit

Status: Within healthy range

Body Fat Calculation

Calculation Breakdown
BMI: 22.9
Age: 30 years
BMI Component: 27.5% (1.20 × 22.9)
Age Component: 6.9% (0.23 × 30)
Constant: -16.2%
Body Fat %: 21.2%
Fit
Body fat percentage between 20-25% for men, 25-30% for women

Body Fat Categories

Essential Athletic Fitness Average Obese
≤10% 11-14% 15-20% 21-25% ≥26%

Body Composition Recommendations

Based on your body fat percentage of 21.2%:

  • Maintain current exercise routine to preserve muscle mass
  • Focus on strength training to build lean muscle
  • Follow a balanced diet with adequate protein intake
  • Monitor body composition changes over time
Important Notes
  • This calculator provides estimates only - actual body fat may vary
  • Deurenberg formula has limitations and may not be accurate for all individuals
  • More accurate methods include DEXA scans, hydrostatic weighing, or skinfold measurements
  • Consult a healthcare professional for comprehensive body composition assessment

Q&A

Q: How accurate is the Deurenberg formula for estimating body fat percentage?

A: The Deurenberg formula has both strengths and limitations:

Advantages:

  • Simple: Only requires BMI and age, which are easily obtainable
  • Correlation: Shows reasonable correlation with actual body fat in healthy populations
  • Accessibility: Useful when more sophisticated methods aren't available

Limitations:

  • Population bias: Developed on European populations, may not be accurate for other ethnicities
  • Muscle mass ignored: Doesn't account for differences in lean body mass
  • Age factor: Assumes linear relationship between age and body fat, which isn't always true
  • Gender: Doesn't differentiate between male and female body composition patterns

Accuracy: Generally within ±4-6% of actual body fat percentage measured by gold standard methods. For more precise measurements, consider DEXA, hydrostatic weighing, or air displacement plethysmography.

Q: What are healthier ways to measure body composition?

A: There are several more accurate methods for measuring body composition:

Gold Standard Methods:

  • DEXA Scan: Dual-energy X-ray absorptiometry - most accurate method
  • Hydrostatic Weighing: Underwater weighing - highly accurate
  • Air Displacement: Bod Pod technology - accurate and comfortable

Field Methods:

  • Skinfold Measurements: Using calipers by trained professionals
  • Bioelectrical Impedance: Handheld devices or scales
  • Bod Pod: Air displacement method (less accessible)

Tracking Methods:

  • Progress Photos: Visual assessment over time
  • Measurements: Waist, hips, arms, thighs circumference
  • Body Shape: How clothes fit and overall appearance

For most people, tracking changes over time with multiple methods provides better insight than relying on a single measurement.

About

Health & Fitness Team
This calculator was created by our Health & Fitness Team , may make errors. Consider checking important information. Updated: April 2026.