How to use it
- Enter your weight in kilograms.
- Enter your height in centimeters.
- Select your age and sex.
- Click the calculate button to see your body‑fat %.
What it does – The calculator takes your weight, height, age and sex, computes your BMI and then applies the NIH body‑fat formula to give a single percentage. Why it matters – Body‑fat % tells you how much of your weight is fat versus lean tissue, a better health indicator than weight alone. How to read – 6‑13 % is typical for athletic men, 14‑24 % is average, above 25 % may signal excess fat. Knowing this number helps you choose the right training intensity and calorie intake. It also lets you compare against age‑ and sex‑specific norms without a lab visit. Example: a 70 kg, 175 cm, 30‑year‑old male gets 18.1 % body fat.
Pro tips
- Round the result to one decimal for easier tracking.
- Enter height in centimeters, not meters, to avoid calculation errors.
- If you’re unsure of your sex value, remember 1 = male, 0 = female.
- Double‑check age entry; a one‑year mistake shifts the result by 0.23 %.
Real-life examples
- A beginner wants to know if they’re too lean before starting a bulk plan.
- A trainer needs a quick estimate to set client cardio targets.
- Someone tracking progress after a diet wants an objective metric.
Case study
Emily, 28, tracked her body fat weekly. After using the calculator, she cut her intake and saw her percentage drop from 29% to 22% in two months, confirming her diet was effective.