BMI Calculator

BMI Calculator (NIH Standard)

This Body Mass Index (BMI) calculator is designed according to NIH (National Institutes of Health) standards. It helps you understand whether your weight is within a healthy range based on your height, weight, and age.

The calculator supports multiple height and weight units and automatically converts values to ensure accurate results.

How to Use the BMI Calculator

Enter Your Age

• Enter your age in years

• BMI categories are mainly intended for adults (18+)

Enter Your Height

You can enter height in any ONE format:

• Feet

• Inches

• Centimeters (cm)

👉 As soon as you enter one value:

• The calculator automatically converts it into the other height units

• You do not need to fill all fields manually

Example:

• Enter 170 cm → Feet and Inches are filled automatically

• Enter 5 feet → Inches and cm are calculated automatically

Enter Your Weight

You can enter weight in any ONE format:

• Kilograms (kg)

• Pounds (lb)

• Stones (st)

👉 The calculator will automatically convert your input into the other units.

Example:

• Enter 70 kg → Pounds and Stones are calculated automatically

• Enter 154 lb → Kilograms and Stones are calculated automatically

Click “Calculate BMI”

Once height, weight, and age are entered, click the Calculate BMI button to see your result.

Understanding Your BMI Result

Understanding Your BMI Result

Your BMI will fall into one of the following categories:

Category                       BMI Range

Underweight                 Below 18.5

Healthy Weight           18.5 – 24.9

Overweight                 25.0 – 29.9

Obese                        30.0 and above

A color-coded bar below the calculator visually explains these categories to make results easy to understand.

⚠️ Important Medical Notice

• BMI is a screening tool, not a diagnosis

• For children and teenagers (under 18), BMI percentile charts should be used instead of standard BMI categories

• Athletes or people with high muscle mass may have a higher BMI without excess body fat

For personalized medical advice, consult a qualified healthcare professional.