Body Fat Calculator

What is Body Fat Calculator?

The Body Fat Calculator estimates your body fat percentage using the US Navy body circumference method. It uses waist, neck, and height measurements (plus hip for women) to provide a reliable estimate without needing calipers or DEXA scans.

How to Estimate Body Fat Percentage

1. Enter your height in centimetres
2. Measure and enter your waist circumference at navel level
3. Measure and enter your neck circumference
4. For women: also measure and enter hip circumference
5. Click Calculate to see your estimated body fat percentage and category

How Body Fat Calculator is Calculated

Men: BF% = 495 / (1.0324 − 0.19077 × log(waist − neck) + 0.15456 × log(height)) − 450. Women: add hip measurement to the formula. Based on the US Navy body composition assessment method.

Worked Example

Male, waist 86 cm, neck 38 cm, height 175 cm: BF% = ~20%. Classification: Average/Acceptable. Target for fitness: 12–18%. Essential fat minimum: 2–5%.

Common Use Cases

• Fitness level assessment
• Weight loss progress tracking
• Body composition monitoring
• Health risk evaluation

Common Mistakes to Avoid

• Measuring waist at the wrong location — measure at the navel level (narrowest point of the torso), not at the belt line or hip bones.
• Pulling the tape too tight or too loose — the tape should be snug against the skin without compressing it.
• Comparing body fat percentage with BMI — they measure different things. A muscular person can have a high BMI but low body fat.
• Expecting extreme accuracy — this is an estimate. The US Navy method has a typical error margin of 3–4%. DEXA scans are more precise.

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