Body Fat Percentage Calculator
What is body fat percentage?
Body fat percentage estimates how much of your body is composed of fat versus lean tissue (muscle, bone, organs, water). It’s more informative than weight alone for tracking physique and health trends over time.
This calculator uses the U.S. Navy circumference method for an accessible at-home estimate.
How the calculator works
- Select Male or Female (hips required for female).
- Choose Metric or Imperial.
- Measure and enter height, neck, waist, and hip (female).
- Press Calculate to get your estimated body fat %.
- Use Copy/Share to save or send your result.
How to measure correctly
- Height: Stand tall without shoes; back to wall for accuracy.
- Neck: Tape just below the larynx (Adam’s apple), relaxed posture.
- Waist: Horizontal tape at navel level (male) or natural waist (female), not sucked in.
- Hips (female): Widest point over the buttocks, tape level to floor.
- Measure against bare skin, not over clothing. Keep tape snug but not compressing.
Tip: Take 2–3 readings for each location and use the average.
U.S. Navy formulas (inches)
Male
%BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Female
%BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
Metric entries are converted internally before applying these equations.
Typical body fat % categories
Male
Female
Ranges are approximate and can vary by age, ethnicity, and organization.
Helpful tips
- Measure at the same time of day (morning is consistent).
- Relax and breathe normally—don’t suck in the abdomen.
- Track trends over weeks; single readings can fluctuate.
- Combine with waist size and photos for better progress checks.
Common mistakes
- Mixing unit systems (cm with inches).
- Pulling the tape too tight or holding it too loose.
- Measuring different waist/hip levels each time.
Frequently asked questions
How accurate is the U.S. Navy method?
It’s reasonably accurate for population use, but individual error can occur from tape placement or body shape. Use consistent technique and track trends.
Why do different tools give different results?
Different equations (Navy, Jackson–Pollock, Deurenberg, BIA scales) and rounding rules can produce varying estimates.
Do I need to lose fat to be healthy?
Health isn’t defined by a single number. Consider habits, fitness, labs, and medical guidance alongside body composition.
Important note
Body fat % is an estimate and does not replace medical evaluation. For a full assessment, consult a qualified professional.