Body Fat Calculator

What is the Body Fat Calculator?

Estimate body fat percentage using the U.S. The U.S. Navy method estimates body fat from a few tape measurements, which makes it easy to track at home without special equipment.

How to use the Body Fat Calculator

1. Enter your sex, your height, your neck, your waist and the remaining fields.
2. Results update automatically as you type; you can also press Calculate.
3. Read the output: body fat, fat mass, lean mass.
4. Use the 📊 chart to see the result visually, then copy or share it.

Formula and method

Worked example

With sex = Male, height = 178 cm, neck = 38 cm, waist = 85 cm, hip = 95 cm, the Body Fat Calculator returns body fat: 16.4%; fat mass: 12.8 kg; lean mass: 65.2 kg.

Where the Body Fat Calculator helps in real life

You are lifting weights and your scale weight is not changing, but your clothes fit differently. Measuring neck and waist each month shows whether body fat is falling while muscle is maintained.

Your fitness tracker gives a body fat number that jumps around. Comparing it with this tape-measure estimate gives you a second reference.

Common mistakes to avoid

• Measuring the waist at different spots each time.
• Pulling the tape too tight or holding your breath.
• Mixing inches and centimeters across measurements.
• Expecting the estimate to match a DEXA scan exactly.

💡 Practical tip: Measure the waist at the navel for men, and at the narrowest point for women, as the Navy method specifies.

Tips for better results

• Measure at the same time of day, ideally in the morning.
• Take each measurement twice and use the average.
• Track the trend over months rather than single readings.

⚠️ This tool provides general information and is not medical advice. It is not a substitute for diagnosis or treatment by a qualified healthcare professional.

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