BMI Calculator

Estimate body mass index from height and weight and place the result inside the usual adult BMI screening bands.

Preparing BMI Calculator

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Input

Choose metric or imperial units, enter height and weight, and the calculator will estimate BMI with the matching screening category. This tool shows the result instantly without step-by-step output.

Input summary

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How to use BMI Calculator

Enter your height and weight in the unit system you prefer, and the calculator will turn those measurements into a BMI estimate and screening range.

What this calculator is for

This calculator is for a quick weight-for-height screening measure. BMI is widely used in public health and primary care, but it does not diagnose health conditions on its own and does not directly measure body fat.

Tips

Use current measurements rather than old values if you want the most meaningful screening result.
BMI is a screening tool, so muscle mass, body composition, and health history still matter.
If the result raises concerns, use it as a prompt for a fuller conversation with a qualified clinician rather than as a diagnosis by itself.

Formula used

This calculator uses the standard body mass index equation. Metric and imperial inputs are just two ways of reaching the same BMI result.

Metric: BMI = weight (kg) ÷ [height (m)]².
Imperial: BMI = weight (lb) ÷ [height (in)]² × 703.
Adult screening bands used here: underweight < 18.5, healthy 18.5–24.9, overweight 25.0–29.9, obesity ≥ 30.0.