Body Fat Calculator

100% free · Runs 100% in your browser · No signup needed

Medical disclaimer: This calculator is for informational purposes only and is not medical advice. Always consult a qualified healthcare professional for medical decisions.

Gender

Male Female

Height (cm)

Neck circumference (cm)

Measure just below the Adam's apple, tape snug but not tight.

Waist circumference (cm)

Men: at the navel. Women: at the narrowest point.

Hip circumference (cm) (women only)

Measure at the widest point of the hips.

Body fat percentage (US Navy method)

Enter your measurements above and the result appears here.

Sur Body Fat Calculator

What is the Body Fat Calculator?

The Body Fat Calculator is a free online fitness tool that estimates your body fat percentage from simple tape-measure readings. Body fat percentage tells you far more about your health and physique than weight alone: two people can weigh exactly the same while one is lean and athletic and the other carries excess fat. Healthy ranges are roughly 10 to 20 percent for men and 18 to 28 percent for women, with athletes lower and higher values signaling increased health risk.

This calculator uses the U.S. Navy body fat formula, developed from extensive military research and validated against underwater weighing. For men it needs neck and waist circumference plus height; for women it adds the hip measurement. The logarithmic equation converts those circumferences into a body fat estimate that is typically within 3 to 4 percent of laboratory methods, all from a two-dollar tape measure.

How to Use the Body Fat Calculator

Select your sex: Choose male or female, since the Navy formula uses different measurement sites for each.
Measure your neck: Wrap the tape just below the Adam's apple, keeping it level and snug but not tight.
Measure your waist: Measure at the narrowest point, usually just above the navel. Breathe out normally first.
Measure hips (women): Women also measure around the widest part of the hips and buttocks.
Enter height and calculate: Add your height, click calculate, and read your body fat percentage with its fitness category.

Key Benefits

Navy-validated method: Based on the research-backed U.S. Navy circumference formula.
No special equipment: A simple tape measure is all you need, no calipers or scales.
Better than BMI: Distinguishes fat from muscle, which BMI cannot do.
Track progress: Re-measure monthly to see fat loss even when the scale stalls.
Free with no signup: Unlimited estimates, and your measurements stay private in your browser.

Pro Tips

Measure in the morning: Take readings before eating for the most consistent waist numbers.
Keep the tape level: A tilted tape adds centimeters of error. Use a mirror to check.
Do not suck in your stomach: Measure relaxed for honest, comparable results.
Focus on the trend: Single readings have a few percent of error, but the direction over months is what counts.

Frequently Asked Questions

How accurate is the Navy body fat formula?

It is typically within 3 to 4 percent of lab methods like DEXA for most people. It is less precise for very muscular or very obese individuals.

What is a healthy body fat percentage?

General fitness guidelines suggest 14 to 24 percent for men and 21 to 31 percent for women, with athletes at the lower ends.

Why is body fat better than BMI?

BMI only uses height and weight, so muscular people can score as overweight. Body fat percentage measures actual composition.

How often should I measure?

Once every two to four weeks is ideal. Daily measurements bounce around too much to be useful.

Related Tools

Compare with the BMI Calculator, set calorie targets using the Calorie Calculator, and find your healthy range with the Age Calculator.

Medical Disclaimer: This calculator is for informational and educational purposes only and is not medical advice. Body fat estimates are approximate and cannot diagnose health conditions. Always consult a qualified healthcare professional for personalized health assessment.

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