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BMI Calculator

Calculate your Body Mass Index in seconds. Enter your weight and height to get your result according to WHO classification.

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Body Mass Index

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Ideal weight for your height:

BMI and age

BMI interpretation may vary by age. For children and teenagers, specific growth charts are used. For people over 65, a slightly higher BMI (23-28) may be associated with better health outcomes. Consult a healthcare professional for personalised advice.

BMI for women and men

BMI calculation is identical for women and men. However, interpretation may differ slightly: women naturally have a higher body fat percentage. WHO reference charts remain the same for both sexes in adults.

BMI by height

1.50 m 1.55 m 1.60 m 1.65 m 1.70 m 1.75 m 1.80 m 1.85 m 1.90 m 1.95 m 2.00 m
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How to calculate and interpret your BMI

Body Mass Index (BMI) is a simple and quick indicator to assess an adult's body size. Developed by Belgian statistician Adolphe Quetelet in the 19th century, it is widely used by the World Health Organization (WHO) as a screening tool for weight problems. The formula is simple: BMI = weight (kg) / height² (m²).

For example, a person weighing 70 kg and measuring 1.75 m has a BMI of 70 / (1.75 × 1.75) = 22.9, which corresponds to normal weight. A BMI between 18.5 and 25 is considered normal for adults. Below 18.5 is underweight; above 25 is overweight; above 30 is obesity.

However, BMI has limitations. It does not distinguish muscle mass from fat mass: a muscular athlete may have a high BMI without being overweight. It also does not account for fat distribution (abdominal or peripheral), age, gender, or ethnicity. This is why BMI should be interpreted as a screening indicator, not as a definitive medical diagnosis.

This calculator also displays your theoretical ideal weight for your height — the weight range corresponding to a BMI between 18.5 and 25. All calculations are performed locally in your browser — no data is sent to a server. For personalised health monitoring, consult a professional (doctor, dietitian, nutritionist).

Frequently asked questions about BMI

The BMI formula is: weight (kg) divided by height squared (m²). For example, for 70 kg and 1.75 m: 70 / (1.75 × 1.75) = 22.9. Use our calculator above to get the result instantly.
According to WHO, a BMI between 18.5 and 25 corresponds to normal weight for adults. This range is associated with the lowest risk of weight-related chronic diseases. However, the ideal BMI may vary by age, gender, and body composition.
BMI calculation is identical for women and men. However, interpretation may differ slightly because women naturally have a higher body fat percentage than men. WHO reference charts remain the same for both sexes in adults.
Yes. WHO reference charts for BMI apply to adults aged 18 to 65. For children and teenagers, specific growth curves are used. In elderly people (over 65), a slightly higher BMI (23-28) may be associated with better health.
BMI does not distinguish muscle mass from fat mass. A muscular athlete may have a high BMI without being overweight. It does not account for fat distribution (abdominal or subcutaneous) or body composition. Other measures (waist circumference, bioimpedance) can complement the assessment.
Ideal weight corresponds to a BMI between 18.5 and 25. Multiply your height squared (in metres) by 18.5 (lower limit) and 25 (upper limit). For example, for 1.70 m: ideal weight between 1.70² × 18.5 = 53.5 kg and 1.70² × 25 = 72.3 kg. Our calculator automatically displays this range.
No. All calculations are performed directly in your browser using JavaScript. No personal data (weight, height) is transmitted to our servers. You can even use this tool offline once the page is loaded.