BMI Calculator

Calculate your Body Mass Index from height and weight

Disclaimer: This BMI calculator is for general information and education only. It is not medical advice, diagnosis, or treatment. BMI does not measure body fat directly and may not suit all individuals. Consult a qualified healthcare professional for personal health decisions.

What is a BMI Calculator?

A BMI (Body Mass Index) calculator estimates whether your weight is in a healthy range for your height. Enter height and weight in metric (cm/kg) or imperial (ft/in and lbs) units to get your BMI score and a standard adult category such as underweight, normal, overweight, or obese. The tool runs entirely in your browser — your data is not sent to our servers.

How to Use This BMI Calculator

  1. Choose Metric or Imperial units at the top of the tool.
  2. Enter your height and weight in the fields shown.
  3. Click Calculate BMI to see your BMI value and category.
  4. Switch units anytime to compare results in cm/kg or ft/in and lbs.

Formula & Notes

Metric: BMI = weight (kg) ÷ height (m)². Example: 70 kg and 1.70 m → BMI ≈ 24.2.

Imperial: BMI = 703 × weight (lbs) ÷ height (in)².

Standard adult categories (WHO): under 18.5 underweight; 18.5–24.9 normal; 25–29.9 overweight; 30+ obese. Categories may differ for some populations, athletes with high muscle mass, older adults, or children.

Frequently Asked Questions

What is a healthy BMI for adults?

For most adults, a BMI between 18.5 and 24.9 is often classified as normal weight. Below 18.5 is underweight, 25–29.9 overweight, and 30 or above obese. Your doctor may interpret results differently based on your health history.

Is BMI accurate for athletes or muscular people?

BMI uses only height and weight, so people with high muscle mass may score “overweight” despite low body fat. It is a screening tool, not a full body-composition test. Athletes and very muscular individuals should use additional measures with a professional.

Does this calculator support metric and imperial units?

Yes. Toggle between metric (centimeters and kilograms) and imperial (feet, inches, and pounds). The same standard BMI formula is applied after converting inputs appropriately.

Is my height and weight stored or uploaded?

No. Calculations run locally in your browser. We do not receive or store the numbers you enter unless you choose to share them yourself.

Can I use this BMI calculator on my phone?

Yes. The tool is mobile-friendly and works in modern browsers on phones, tablets, and desktops without installing an app.

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