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BMI Calculator – Body Mass Index by Height & Weight

Body Mass Index (BMI) is a screening number calculated from height and weight that the WHO uses to classify adults into weight status categories. Though it doesn't measure body fat directly, it correlates well with health risk at the population level and requires only a scale and measuring tape — making it the most accessible starting point for weight assessment.

This BMI calculator works for adults 18+ in metric (kg/cm) and imperial (lb/in) units. It returns your BMI score, weight category, healthy weight range for your exact height, and how far you are from the normal range if outside it.

How to use the Bmi Calculator

Choose metric or imperial units.

Enter your height.

Enter your current weight.

View BMI score, weight category, and healthy weight range for your height.

WHO Adult BMI Classification
BMI	Category	Health Risk
< 18.5	Underweight	Nutritional deficiency, bone density loss
18.5–24.9	Normal weight	Lowest risk for weight-related conditions
25.0–29.9	Overweight	Increased cardiovascular and metabolic risk
30.0–34.9	Obese Class I	High risk
35.0–39.9	Obese Class II	Very high risk
≥ 40.0	Obese Class III (Severe)	Extremely high risk

Bmi Calculator FAQ

Is BMI accurate for muscular or athletic people?

No. BMI uses total body weight and can't distinguish muscle from fat. Heavily muscular individuals often score 'overweight' or 'obese' despite very low body fat. Body fat percentage measurements are more appropriate for athletic populations.

Does BMI apply to children?

No. Children use age- and sex-specific BMI-for-age percentile charts. A BMI of 22 means different things at different ages for a child.

What is a healthy BMI for men vs women?

The threshold ranges (18.5–24.9 normal) are the same for both sexes, but healthy body fat percentages differ. Women naturally carry more body fat than men, so a muscular man and an average woman at the same BMI have different body compositions.

What other measures complement BMI?

Waist circumference (visceral fat indicator), waist-to-hip ratio, body fat percentage (DEXA, Navy method), and blood markers (cholesterol, blood pressure, blood glucose) together give a more complete picture of metabolic health risk.