Body fat percentage is the proportion of your weight that is fat (versus muscle, bone, water, organs). The calculator uses the US Navy method, which estimates body fat from height plus a few circumference measurements (neck, waist, hip for women) — accurate to ±3% for most people.
What is Body Fat?
BMI tells you nothing about what your weight is made of. Two people at 80 kg can have wildly different body fat — one mostly muscle, one mostly fat. Body fat percentage is the better metric for actual fitness, but measuring it precisely requires lab equipment (DEXA scans, hydrostatic weighing, or BIA scales).
The US Navy method, developed in the 1980s, gets close to lab-grade accuracy using only a measuring tape. You measure neck and waist (and hip for women), plug into a formula along with your height, and get a body fat estimate within ±3% of true value for most people. Bodybuilders and very obese people see slightly larger errors.
Body fat ranges differ by sex. Athletes are 6-13% (men) or 14-20% (women). Fitness range is 14-17% / 21-24%. Average is 18-24% / 25-31%. Above that = high body fat = elevated metabolic risk regardless of BMI.
US Navy body fat formula
- waist
- Waist—circumference at navel level, in cm
- neck
- Neck—circumference at midpoint of neck, in cm
- hip
- Hip (women)—circumference at widest point, in cm
- height
- Height—in cm
How to use this calculator
Take your measurements with a soft tape, enter them, get your estimated body fat percentage.
Measure neck
Around the midpoint of your neck — below the larynx for men, at the narrowest point. Tape should be snug, not pulling skin.
Measure waist
At navel level, NOT where your trouser waistband sits. Tape parallel to the floor, snug, after exhaling. Do not suck in.
Measure hip (women only)
At the widest point of the hips, usually around the buttocks. Tape parallel to the floor, snug.
Enter height and gender
Required for the formula.
Read body fat % and category
Athletes, fitness, average, or obese. Compare to your goals.
When body fat % matters
Body recomposition tracking
If you are losing fat and gaining muscle, the scale stays still — but body fat % drops. Track this monthly to see real progress.
Fitness goal-setting
Aim for the fitness band (14-17% men, 21-24% women) for a noticeably lean look without extreme dieting.
Medical risk assessment
High body fat (>25% men, >32% women) is more strongly correlated with metabolic disease than BMI alone.
Athlete preparation
Many sports have target body fat ranges. Boxers cut to specific %s for weight class qualification.
Common mistakes to avoid
Measuring waist at the trousers
Measure at the navel, parallel to floor, after exhaling. Trouser waist is usually 5-10 cm below this — gives an under-estimate.
Pulling the tape tight
Tape should rest on skin without compressing — snug, not tight. Compressing skin gives smaller, falsely-better numbers.
Trusting daily fluctuations
Body fat % varies day to day with hydration. Weekly or monthly trends matter, not daily snapshots.
Glossary
- Body Fat Percentage
- Fat mass as a fraction of total body weight. The most useful single body composition metric.
- Lean Body Mass (LBM)
- Everything that is not fat — muscle, bone, water, organs. Total weight − fat mass.
- Essential fat
- Minimum fat needed for basic body function. ~3-5% for men, 10-13% for women.
- DEXA scan
- X-ray-based gold-standard for body composition measurement. ~₹2,000-5,000 per scan in India.
- BIA scale
- Bioelectrical Impedance Analysis — sends a weak current through your body. Cheap but variable accuracy.