BMI Calculator

What is BMI (Body Mass Index)?

BMI is your weight in kilograms divided by the square of your height in meters — a simple, internationally used indicator of whether your weight is appropriate for your height. For example, at 170 cm and 65 kg, that's 65 ÷ (1.7 × 1.7) ≈ 22.5. It's widely used because it's easy to calculate, but it remains only a reference screening tool.

How to calculate BMI

1. Enter your height — type your height in centimeters.
2. Enter your weight — type your weight in kilograms.
3. Calculate — press the button and your BMI value and weight category appear instantly.

How are the weight categories divided?

Using the WHO international standard, the categories are: underweight below 18.5 · normal weight 18.5–24.9 · overweight 25–29.9 · obese Class I 30–34.9 · obese Class II 35–39.9 · obese Class III (severe obesity) 40 and above.

How do I find my standard weight?

Multiply the normal BMI range (18.5–24.9) by the square of your height in meters to get your standard weight range. For example, at 170 cm that's 18.5×1.7² ≈ 53 kg up to 24.9×1.7² ≈ 72 kg as the normal weight range.

Can BMI alone determine my health?

No. BMI can't distinguish muscle from fat, so people with a lot of muscle may read higher than they really are, while those with little muscle may read lower. For an accurate assessment, it's best to also check body fat percentage, waist circumference, blood pressure, and blood sugar.

Do the same standards apply to children, pregnant women, and athletes?

No. Growing children and adolescents are assessed with age- and sex-specific percentiles (growth charts), pregnant women are evaluated against their pre-pregnancy weight, and highly muscular athletes may have a high BMI without being obese. These cases need interpretation by a professional.