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BMI Calculator

Calculate your Body Mass Index with metric or imperial units, category, and healthy weight range.

Height (cm)

Weight (kg)

BMI Categories (WHO)

BMI Range	Category
Below 18.5	Underweight
18.5 – 24.9	Normal weight
25.0 – 29.9	Overweight
30.0 and above	Obese

About BMI Calculator

BMI Calculator computes your Body Mass Index using the standard WHO formula: weight (kg) / height (m)². Switch between metric (kg/cm) and imperial (lbs/ft-in) units. The tool instantly shows your BMI value, weight category (Underweight, Normal, Overweight, Obese), a color-coded visual scale, and the healthy weight range for your height.

How to Use

Choose your unit system Click "Metric" for kg/cm or "Imperial" for lbs/ft-in. The form fields update automatically.

Enter height and weight Type your height and weight. Your BMI calculates automatically as you type.

Read your BMI category See your BMI number, weight category, color-coded scale, and healthy weight range for your height.

Check the WHO categories table Scroll down to see the full WHO BMI classification table with color-coded ranges.

🔒 Privacy note: All processing happens locally in your browser. Your data is never sent to any server.

Why Use BMI Calculator?

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Accurate & Reliable BMI Calculator uses standard mathematical formulas and algorithms, verified against reference implementations. Trust the results for homework, work, or personal use.

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Clear Explanations Get more than just a number. Where applicable, see step-by-step breakdowns, visual representations, and context that helps you understand the result.

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Instant Calculation Results update as you type — no need to press a calculate button or wait for a server response. Real-time feedback helps you explore different scenarios quickly.

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No Data Collection Your inputs are processed locally in your browser. No data is stored, transmitted, or used for any purpose. Close the tab and everything is gone.

Frequently Asked Questions

BMI (Body Mass Index) = weight(kg) / height(m)². It's a screening tool used to classify weight status. It does not measure body fat directly or account for muscle mass, age, or sex.

BMI is a simple screening tool but has limitations. Athletes may have high BMI due to muscle mass. It also doesn't distinguish between fat distribution or account for differences in populations.

The WHO classifies 18.5–24.9 as "normal weight." However, some health organizations use slightly different thresholds for different ethnic groups.

BMI may overestimate body fat for athletes and muscular individuals because it doesn't distinguish between muscle and fat mass. For these cases, body fat percentage or waist-to-hip ratio may be more accurate indicators.

A healthy BMI range is 18.5 to 24.9 according to the WHO. Below 18.5 is underweight, 25-29.9 is overweight, and 30+ is obese. However, these ranges may vary by age, sex, and ethnicity.