What is body fat percentage?

Body fat percentage is the proportion of fat in the body compared to total body weight. It helps assess body composition and health risk better than weight alone.

Which method is most accurate?

Clinical methods (DEXA, hydrostatic weighing) are most accurate. US Navy and BMI-based formulas provide reasonable estimates for general use but have limitations.

What measurements does the US Navy method require?

For men: neck and waist (at navel). For women: neck, waist, and hip. All measurements should be in cm (or inches if using imperial).

Can athletes use these formulas?

Athletes with high muscle mass may get misleading results; consider professional body composition testing for precise values.

Is body fat % the only health metric I need?

No. Use body fat % alongside blood tests, blood pressure, fitness, diet, and medical advice for a complete health picture.

Body Fat Percentage Calculator

Estimate your body fat % using the US Navy method (recommended) or a BMI-based estimate. Enter measurements, your name and optionally upload an image — result will show name & image with tailored health tips.

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Gender

Age (years)

Units

Height (cm)

Neck circumference (cm)

Waist circumference (cm)

Weight (kg) — optional

Note: These are estimates. For precise body composition results, clinical tests (DEXA, Bod Pod) are recommended. Use results to guide lifestyle decisions and consult a healthcare professional for personalised advice.

How it works

The US Navy method estimates body fat using circumference measurements — it's practical and commonly used for field assessments. BMI-based estimate is a rougher approximation using BMI and age/sex.

US Navy Formula (metric)

Male: % body fat = 495 / (1.0324 - 0.19077 × log10(waist - neck) + 0.15456 × log10(height)) - 450
Female: % body fat = 495 / (1.29579 - 0.35004 × log10(waist + hips - neck) + 0.22100 × log10(height)) - 450

BMI-based estimate (approx)

Several regression formulas exist; BMI-based methods are less accurate for muscular or elderly people but useful as a quick check.

Interpreting body fat %

Men: Essential 2–5%, Athletes 6–13%, Fitness 14–17%, Average 18–24%, Obese 25%+
Women: Essential 10–13%, Athletes 14–20%, Fitness 21–24%, Average 25–31%, Obese 32%+

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Body Fat Percentage — More details

Body fat percentage is an important indicator of health. Lower or higher than recommended ranges are associated with different health risks. Use this tool regularly to track trends rather than single-point readings.

Limitations

Circumference-based formulas assume certain body shapes and distribution of fat; they may under- or overestimate in some ethnic groups or body types. Always consider multiple measurements and professional advice.

Frequently Asked Questions

How should I measure correctly?

Use a soft cloth tape; measure waist at the level of the navel (or narrowest point if specified), neck below the larynx, hips at the widest point. Keep tape horizontal and snug but not compressing skin.

Are results exact?

No — these are estimates. For clinical accuracy, use DEXA or hydrostatic weighing.

How often should I check?

Check every 2–4 weeks to monitor trends. Avoid daily checks which reflect short-term fluid changes.