Free & private

Online BMI Calculator

Q: What is considered a healthy BMI?

For most adults, a BMI from 18.5 to 24.9 is generally considered the healthy range.

Q: Is BMI an accurate measure of health?

BMI is a screening measure, not a diagnosis. It does not directly measure body fat or account for every individual factor.

Q: Is this online BMI calculator free and private?

Yes. The calculator is free to use, and the measurements are processed locally in your browser rather than uploaded or stored by the tool.

Calculate your body mass index (BMI) from your height and weight, understand your adult BMI category, and see a healthy weight range for your height.

BMIYour result will appear hereAdd your height and weight, then select calculate to see your BMI.

Your body mass index

0.0

UnderweightHealthyOverweightObesity

Healthy weight range for your height

BMI is a general screening tool for adults, not a medical diagnosis. It may not reflect individual factors such as muscle mass, pregnancy, age, or ethnicity. Speak with a healthcare professional for personal advice.

How to use the online BMI calculator

This free BMI calculator works with metric and imperial units. Choose your preferred system, enter your current height and weight, and select calculate. The calculation happens in your browser, so your measurements are not uploaded or stored by this tool.

1. Choose your units

Use kilograms and centimetres, or pounds, feet and inches.

2. Add measurements

Enter accurate, current measurements for a more useful estimate.

3. Review your result

See your BMI category and a reference healthy weight range.

Understanding your BMI result

Body mass index compares weight with height. For most adults, common screening categories are underweight below 18.5, healthy weight from 18.5 to 24.9, overweight from 25 to 29.9, and obesity at 30 or above. These ranges are a starting point only; one number cannot describe overall health.

Metric BMI formula

BMI = weight in kilograms ÷ height in metres squared (kg/m²).

Imperial BMI formula

BMI = 703 × weight in pounds ÷ height in inches squared.

Who should use it?

This calculator uses general adult categories. BMI for children and teens should be interpreted with age- and sex-specific growth charts.

How is BMI calculated?

Metric BMI is weight in kilograms divided by height in metres squared. With imperial measurements, multiply pounds by 703 and divide by height in inches squared.

What is considered a healthy BMI?

For most adults, 18.5 to 24.9 is generally called the healthy range. Guidance can differ for children, pregnancy, older adults, and some ethnic groups.

Is BMI an accurate measure of health?

BMI is a simple screening measure, not a diagnosis. It does not directly measure body fat and cannot account for muscle mass or all individual health factors.

Is this online BMI calculator free and private?

Yes. It is free to use without an account, and your height and weight are processed locally in your browser rather than uploaded or stored by the tool.