BMI Calculator: Check Your Body Mass Index & Healthy Weight Range

Calculate your Body Mass Index (BMI) using metric or imperial units. See your BMI category and the healthy weight range for your height based on CDC guidelines.

Mathematical Audit

BMI Formula

Body Mass Index (BMI) is calculated by dividing your weight by the square of your height. The result is compared against standard CDC weight-status categories for adults, and a healthy weight range is calculated for your exact height.

Metric: BMI = Weight (kg) ÷ Height (m)²
Imperial: BMI = (Weight (lb) ÷ Height (in)²) × 703
Healthy Weight Range (kg) = 18.5 × Height (m)² to 24.9 × Height (m)²

BMI categories for adults aged 20 and older are the same regardless of age or sex: below 18.5 is underweight, 18.5-24.9 is healthy weight, 25-29.9 is overweight, and 30+ is obesity (split into Class 1, 2, and 3). BMI is a screening tool only — it does not directly measure body fat and can be less accurate for very muscular people, athletes, older adults, or pregnant women.

Operational Guide

How to Use the BMI Calculator

1

Choose your unit system

Select Metric (centimeters and kilograms) or Imperial (feet, inches, and pounds) depending on what you know your measurements in.

2

Enter your height

Type in your height in centimeters, or your feet and inches if using imperial units.

3

Enter your weight

Type in your current weight in kilograms or pounds.

4

Click Calculate

Instantly see your BMI value, weight category, and the healthy weight range for your height.

Real-World Scenario Example

"An adult who is 175 cm tall and weighs 70 kg wants to check their BMI."

Inputs

unitSystem:metric
heightCm:175
weightKg:70

Result

BMI = 22.9, which falls in the 'Healthy Weight' category (18.5-24.9). The healthy weight range for 175 cm is approximately 56.7 kg to 76.3 kg.

Important Disclaimer

This calculator provides a BMI estimate for screening purposes only and is not a diagnosis. BMI does not directly measure body fat and may not be accurate for athletes, pregnant women, older adults, or very muscular individuals. Consult a healthcare provider for a complete health assessment.

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