BMI Calculator — Body Mass Index | Metric & Imperial

Weight

Height

Your BMI

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1518.5253040

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Healthy Weight Min

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Healthy Weight Max

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About the BMI Calculator

Body Mass Index (BMI) is a simple numerical measure calculated from a person's height and weight. It was developed in the 19th century by Belgian statistician Adolphe Quetelet and has been used by the World Health Organization as a population-level health screening tool since the 1980s.

BMI categories (WHO standard)

Below 18.5 — Underweight
18.5 – 24.9 — Normal (healthy) weight
25.0 – 29.9 — Overweight
30.0 – 34.9 — Obese Class I
35.0 and above — Obese Class II+

Limitations of BMI

BMI does not distinguish between muscle and fat mass. Athletes and heavily muscled individuals may have a high BMI despite low body fat. Elderly people may have a normal BMI but carry excess fat due to muscle loss. For a complete health picture, BMI should be used alongside other measurements such as waist circumference.

Metric vs imperial

Our calculator supports both metric units (kilograms and centimetres) and imperial units (pounds and inches). Switch between them using the toggle at the top of the calculator — all values convert automatically.

Frequently Asked Questions

What is BMI?

BMI (Body Mass Index) is a measure of body fat based on height and weight. It is calculated by dividing your weight in kilograms by your height in metres squared (kg/m²). It is widely used as a screening tool by healthcare professionals.

What is a healthy BMI?

For most adults, a BMI between 18.5 and 24.9 is considered healthy. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is considered obese. These thresholds may differ for certain ethnic groups.

Is BMI accurate?

BMI is a useful screening tool but not a diagnostic measure. It does not directly measure body fat and may misclassify muscular individuals as overweight. Always consult a doctor for a full health assessment.

Does BMI differ for men and women?

The standard BMI formula is the same for men and women, though body fat distribution differs between sexes. Some clinicians use adjusted scales, but the WHO standard ranges apply to both.

How do I calculate BMI in kg and cm?

Divide your weight in kg by your height in metres squared. For example, 70 kg ÷ (1.75 × 1.75) = 22.9. Our calculator does this instantly — just enter your weight and height.