Body Fat Calculator
Estimate your body fat percentage using the US Navy method.
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Body fat percentage — why it matters more than weight
Your total body weight is a blunt instrument. Two people can weigh exactly the same but have very different body compositions — one might have 15% body fat and significant muscle mass, the other 35% body fat and minimal muscle. The health implications are completely different.
Body fat percentage gives you a better picture of body composition, but measuring it accurately is harder than stepping on scales. Various methods exist with different trade-offs:
- Tape measure methods (Navy formula, waist-to-height): Convenient and reasonably accurate for most people. This calculator uses the US Navy method.
- Bioelectrical impedance (smart scales): Consumer scales send a small electrical current through the body. Quick and convenient but accuracy varies with hydration levels — results can swing 3–5% depending on when you measure.
- Skinfold calipers: Trained practitioners pinch and measure subcutaneous fat at specific sites. Accurate when done correctly, but operator-dependent.
- DEXA scanning: The gold standard — accurate, consistent, and provides a detailed breakdown by body segment. Available at some clinics and universities for $50–100.
🦘 Fun fact: Australian elite athletes are among the most body-composition-tested people in the world — the Australian Institute of Sport (AIS) in Canberra has been using DEXA scanning and other methods since the 1980s to monitor athlete health and performance.
Want a deeper guide?
Read: BMI Is Flawed, But Here's Why It's Still Useful (and What to Use Alongside It) — why BMI alone misses the full picture, and when body fat gives you a better read.
Read the BMI guide →