Body Fat Calculator - Estimate Body Fat Percentage Online Free

How to Use the Body Fat Calculator

1. Select method — US Navy (most accurate) or simple BMI-based estimate
2. Enter measurements — for the US Navy method: neck, waist, and hip (women) circumference
3. Enter your stats — height, weight, age, gender
4. Get body fat % — see your estimated body fat percentage and category
5. View the gauge — the visual indicator shows where you fall on the body fat scale

The US Navy method uses neck, waist, and hip measurements for the most accurate estimate. All data stays in your browser.

Features

• US Navy method — most accurate estimation formula
• BMI-based — quick estimate if measurements aren’t available
• Body fat categories — essential, athlete, fitness, average, obese
• Dual units — imperial and metric
• Visual gauge — see where you fall on the scale

Use Cases

• Fitness progress tracking — monitor body fat changes during a weight loss or muscle building program
• Health assessment — get a more accurate picture of health than BMI alone, especially if you exercise regularly
• Personal training — trainers can track client body fat changes over time to measure program effectiveness
• Competition prep — bodybuilders and fitness competitors track body fat leading up to a show
• Wellness check — understand your body composition as part of a comprehensive health review

FAQ

How accurate is the US Navy method?

The US Navy body fat method has an accuracy of about 2-3% compared to DEXA scans or hydrostatic weighing. It’s one of the most accurate measurement-based estimation methods available without specialized equipment.

What measurements do I need?

For the US Navy method, you need: neck circumference, waist circumference (at navel level), and hip circumference (for women only). Measure at the widest point for consistent results.

What are healthy body fat percentages?

For men: 6-24% is healthy (athletes 6-13%, fit 14-17%, average 18-24%). For women: 16-30% is healthy (athletes 16-23%, fit 24-27%, average 28-30%). Essential fat minimums are 2-5% for men and 10-13% for women.

How often should I measure body fat?

Once every 2-4 weeks is sufficient. Body fat changes slowly, and daily measurements show too much fluctuation due to hydration, food intake, and measurement consistency.

Tips

• Take measurements at the same time of day, ideally in the morning before eating
• Use a flexible measuring tape and keep it level — not too tight or too loose
• The US Navy method is most accurate for people with average body types; very lean or very muscular individuals may get less accurate results