Body Fat Calculator

Gender

Height (cm)Enter a valid height.

Waist (cm, at navel)Enter a valid measurement.

Neck (cm)Enter a valid measurement.

Estimated Body Fat

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How to Use This Tool

Select your gender.
Measure and enter your height, waist (at navel), and neck circumference in cm (women also enter hip circumference).
Click Calculate Body Fat % for your estimate.

The US Navy Body Fat Formula

The US Navy method estimates body fat percentage using only a few circumference measurements and a logarithmic formula, making it a practical alternative to skinfold calipers or DEXA scans for a quick estimate:

Men: % Body Fat = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450

Women: % Body Fat = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450

Why This Method Is Popular

Unlike skinfold calipers (which require training to use accurately) or DEXA scans (expensive, clinical equipment), the US Navy method only needs a simple tape measure, making it accessible for regular self-tracking while still being reasonably accurate for most body types.

Measurement Tips for Accuracy

Measure waist at the navel, not at the narrowest point
Measure neck just below the larynx (Adam's apple)
Take measurements at the same time of day, under similar conditions, for consistent tracking over time

Limitations

This method can be less accurate for very lean athletes or individuals with atypical body fat distribution. For precise body composition analysis, DEXA scans or hydrostatic weighing remain the gold standard.

Frequently Asked Questions

How accurate is the US Navy method?

It's reasonably accurate for most people (typically within a few percentage points of more precise methods like DEXA scans), but can be less reliable for very lean athletes or those with atypical body composition.

Why does the formula differ between men and women?

Men and women have different typical fat distribution patterns, so the formula uses different measurement combinations and coefficients calibrated separately for each to improve accuracy.

Where exactly should I measure my waist for this calculation?

Measure at the navel (belly button) level, not at the narrowest point of your waist, which is a different measurement used for waist-to-hip ratio calculations.

This calculator is provided for general informational and estimation purposes only. Results should not be treated as professional financial, tax, legal, medical, or engineering advice. Always verify critical calculations with a qualified professional or official source before making decisions.