Body Fat Calculator

The calculator applies established formulas to estimate body fat: U.S. Navy Method uses log-based equations with waist, neck, and height for men; waist, hip, neck, and height for women. BMI-Based Formula uses BMI, age, and sex to estimate body fat percentage (Deurenberg formula). Both methods compute Lean Body Mass (LBM) and Fat Mass. The percentage shown is (Fat Mass ÷ Total Weight) × 100.

Healthy body fat ranges differ by sex and age. According to the American Council on Exercise (ACE): Essential fat: Men 2–5%, Women 10–13%; Athletes: Men 6–13%, Women 14–20%; Fitness: Men 14–17%, Women 21–24%; Average: Men 18–24%, Women 25–31%; Obese: Men ≥25%, Women ≥32%.

Monitoring body fat is more meaningful than weight alone. Two people with the same weight can have very different body compositions. Body fat percentage directly reflects how much fat you carry, helping you track fat loss versus muscle gain. Excess fat, especially visceral fat, is linked to higher risk of heart disease, diabetes, and other conditions.

This calculator provides an estimate based on population averages. For clinical precision, lab methods like DEXA or hydrostatic weighing are better. For home use, this calculator is convenient and consistent for tracking trends over time.

Height: Stand straight without shoes. Weight: Use a reliable scale. Waist: Measure at the navel while relaxed. Neck: Measure just below the Adam's apple. Hip (women): Measure around the widest part of the hips. Use a non-stretch tape on bare skin. Don't squeeze the tape too tightly or hold your breath. Measure first thing in the morning for consistency.

Lean Body Mass (LBM) is everything except fat: muscle, organs, bone, water, etc. Our calculator shows LBM in pounds or kg. Maintaining LBM is important for metabolism and strength.

It's best to check monthly rather than daily to see real changes. Always measure under similar conditions (e.g. morning, before meals).

The formulas are generally for adults. For children, teens, or older adults, consult a professional. Norms are mostly based on younger adults.

No. Essential fat is needed for hormone and organ function. Excessively low body fat can be unhealthy. Always interpret your number along with how you feel and under medical guidance.