Free Body Fat Percentage Calculator
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Body Fat Percentage Calculator

Compare multiple estimation methods side by side. See where you rank versus age- and gender-matched cohorts.

For informational purposes only. This is not medical advice. Body fat estimates from circumference-based formulas have ±3-4% error margins. Consult a healthcare provider for clinical assessments.

Your Measurements

Measured at navel
Optional: Skinfold Measurements (mm)

For Jackson-Pollock 3-site estimate. Requires calipers.

Results

Enter your measurements and click Calculate to see body fat estimates from multiple methods, your percentile ranking, and personalized guidance.

How Body Fat Percentage Is Estimated

This calculator provides estimates using up to three methods, each with different inputs and accuracy trade-offs:

U.S. Navy Method

Uses height and circumference measurements (neck, waist, and hips for women) to estimate body fat. Developed by Hodgdon and Beckett at the Naval Health Research Center. Accuracy is within ±3-4% for most people. No special equipment needed — just a tape measure.

Jackson-Pollock 3-Site Method

Uses skinfold caliper measurements at three anatomical sites to estimate body density, converted to body fat percentage via the Siri equation. More accurate than circumference methods (±2-3%) but requires calipers and correct technique. Sites differ by sex: chest/abdomen/thigh (men) or triceps/suprailiac/thigh (women).

BMI-Derived Estimate

Uses the Deurenberg equation to convert BMI into an estimated body fat percentage, accounting for age and sex. Least accurate for muscular or very lean individuals, but useful as a rough cross-check requiring only height and weight.

Understanding Your Percentile

The percentile gauge shows where your body fat percentage falls compared to others of the same sex and age group, based on NHANES population data. The 50th percentile means half the population has a higher value and half has lower. Being below the 50th percentile is generally favorable from a health perspective, though extremely low body fat carries its own risks.

Limitations

All estimation methods have error margins. Individual factors like bone density, hydration status, and fat distribution patterns affect accuracy. These calculators work best for tracking changes over time using consistent measurement technique. For clinical decisions, use a DEXA scan, BodPod, or hydrostatic weighing.

Frequently Asked Questions

How accurate is a body fat percentage calculator?

Online calculators using the U.S. Navy method or skinfold formulas are typically accurate within ±3-4% for most people. They're best used for tracking trends over time rather than pinpointing an exact number. For clinical accuracy, consider DEXA scans or hydrostatic weighing.

What is the U.S. Navy body fat formula?

The U.S. Navy method estimates body fat using circumference measurements — neck, waist (and hips for women). For men: 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76. For women: 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387. All measurements in centimeters.

What is a healthy body fat percentage?

Healthy ranges vary by age and sex. For men aged 20-39: 8-19% is considered healthy. For women aged 20-39: 21-33% is healthy. Essential fat (below which health risks increase) is approximately 2-5% for men and 10-13% for women. Athletes typically carry 6-13% (men) or 14-20% (women).

How do I measure my waist and neck for the Navy method?

Measure your waist at the narrowest point (usually at the navel). Measure your neck just below the larynx (Adam's apple), sloping slightly downward at the front. For women, also measure hips at the widest point. Use a flexible tape measure, keep it level, and don't pull too tight.

What is the Jackson-Pollock method?

The Jackson-Pollock method uses skinfold caliper measurements at 3 or 7 body sites to estimate body density, which is then converted to body fat percentage using the Siri equation. The 3-site version measures chest, abdomen, and thigh for men; triceps, suprailiac, and thigh for women. It requires calipers but is more accurate than circumference-only methods.