#1473 · Health Tool

Fitness Body Fat Calculator

Estimate body fat percentage, fat mass, lean body mass, FFMI, ideal body fat gap, and a body composition score using body measurements.

Calculator

Health inputs
cm
kg
cm
cm
cm
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How to use this calculator

Enter height, weight, waist, neck, hip, and gender. The calculator applies the US Navy body fat equation and estimates lean mass, fat mass, FFMI, and body composition status.

What the result means

Body fat percentage is often more useful than body weight alone because it separates fat mass from lean mass. Use it to plan fat-loss goals while protecting muscle.

Male: 86.010×log10(waist-neck)-70.041×log10(height)+36.76. Female: 163.205×log10(waist+hip-neck)-97.684×log10(height)-78.387.

Measurements must be taken consistently. This is not a medical body composition test.

Example calculation

A 175 cm, 82 kg male with 88 cm waist and 39 cm neck is estimated near 22% body fat, with about 64 kg lean mass and 18 kg fat mass.

Tips for better results

  • Measure waist at the same time of day.
  • Track body fat trend, not one isolated value.
  • Use strength training and protein intake to preserve lean mass.

FAQ

What is a healthy body fat percentage for adults?

Healthy ranges depend on gender and age, but many men target roughly 10–20% and many women target roughly 18–28% for general fitness.

How much fat should I lose to reach athletic body fat?

The calculator estimates fat mass and goal fat mass, then shows the approximate fat loss needed for a selected fitness range.

Is BMI or body fat percentage more accurate?

Body fat percentage is usually more informative for body composition because BMI does not separate fat from muscle.

What is FFMI and why does it matter?

FFMI estimates lean mass relative to height and helps evaluate muscularity beyond body weight alone.

How long does it take to reduce body fat percentage?

A sustainable pace often requires several weeks or months depending on calorie deficit, training, sleep, and starting body fat.

Decision modules

ModuleWhat it shows
Health Score0-100 decision score based on the calculator inputs.
Body Fat EstimateUses body measurements to estimate body fat.
Lean MassShows non-fat body mass.
FFMIRates lean mass relative to height.
Goal GapEstimates fat loss needed for a better category.

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