BMI (Body Mass Index) is a measure of body fat based on height and weight. It is calculated as weight (kg) divided by height (m) squared. For imperial units: (weight in lbs / height in inches²) × 703.

What is a healthy BMI?

According to the WHO, a BMI of 18.5—24.9 is considered normal weight. Below 18.5 is underweight, 25—29.9 is overweight, and 30 or above is obese.

Does BMI apply to everyone?

BMI is a screening tool, not a diagnosis. It may not be accurate for athletes (high muscle mass), elderly people, pregnant women, or children. Different ethnic groups may also have different risk thresholds.

Does this support both metric and imperial?

Yes. Switch between metric (kg and cm) and imperial (pounds, feet and inches) using the toggle at the top.

Is BMI accurate for everyone?

BMI is a screening tool, not a diagnosis. It may not be accurate for athletes (high muscle mass), elderly people, pregnant women, or children.

What is the BMI formula?

For metric: BMI = weight (kg) ÷ height (m)². For imperial: BMI = (weight in lbs ÷ height in inches²) × 703.

Does BMI calculation send my health data anywhere?

No. The BMI formula runs entirely in your browser using JavaScript. Your weight and height values are used only for the on-screen calculation and are never transmitted to any server or stored by Irreva.

BMI Calculator — Body Mass Index Calculator Free Online

Calculate your BMI (Body Mass Index) instantly. Supports metric (kg/cm) and imperial (lbs/ft). See your healthy weight range. Free, no sign-up.

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What is BMI Calculator — Body Mass Index Calculator Free Online?

BMI (Body Mass Index) is a numerical value calculated from a person's weight and height. It is used as a screening tool to categorize individuals as underweight, normal weight, overweight, or obese. The formula is: BMI = weight (kg) ÷ height (m)². For imperial units: BMI = (weight in lbs ÷ height in inches²) × 703. Our BMI Calculator supports both metric and imperial units, shows your BMI category with color coding, and displays the healthy weight range for your height. Note that BMI is a screening tool, not a medical diagnosis.

How to Use BMI Calculator — Body Mass Index Calculator Free Online

1Select your measurement system: Metric (kg/cm) or Imperial (lbs/ft).
2Enter your weight in kilograms (or pounds for imperial).
3Enter your height in centimeters (or feet and inches for imperial).
4Your BMI is calculated instantly and displayed with your category.
5Review the healthy weight range shown for your height.

Key Features

Supports metric (kg/cm) and imperial (lbs/ft) units
Instant BMI calculation as you type
Color-coded BMI categories (Underweight, Normal, Overweight, Obese)
Visual gauge bar showing your position on the BMI scale
Healthy weight range displayed for your height

Benefits

Quickly assess your weight status relative to your height
Track BMI changes over time
Understand healthy weight ranges for your body
Use as a starting point for health and fitness goals

Use Cases

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Why Use Irreva for BMI Calculator — Body Mass Index Calculator Free Online?

Quickly assess your weight status relative to your height

Track BMI changes over time

Understand healthy weight ranges for your body

Runs 100% in your browser — files never leave your device.

No account, no sign-up, no subscription — free forever.

Works on any device: desktop, tablet, or mobile.

Frequently Asked Questions

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