BMI Calculator

How to Calculate Your BMI

Enter your weight and height, choose between metric (kg/cm) or imperial (lb/inches) units, and optionally enter your age. Click Calculate to see your Body Mass Index instantly. The tool shows your BMI score, which category it falls into, and a visual scale showing where you stand. It also displays your healthy weight range and the weight difference to reach normal BMI.

What Is BMI?

Body Mass Index (BMI) is a simple calculation using your height and weight to estimate body fat. The formula is weight (kg) divided by height (m) squared. While BMI is widely used by healthcare professionals as a quick screening tool, it has limitations — it doesn’t distinguish between muscle and fat, and doesn’t account for age, gender, or body composition. Athletes with high muscle mass may have a high BMI despite being very fit.

Despite its limitations, BMI remains one of the most commonly used health metrics because of its simplicity. It’s a useful starting point for understanding your weight status, but should be considered alongside other factors like waist circumference, body fat percentage, and overall fitness level.

BMI Categories

The World Health Organization defines BMI categories as follows: Underweight is below 18.5, Normal weight is 18.5 to 24.9, Overweight is 25 to 29.9, Obese Class I is 30 to 34.9, and Obese Class II+ is 35 and above. These ranges apply to adults aged 20 and older. For children and teenagers, BMI is interpreted differently using age-specific percentiles.

Frequently Asked Questions

Is BMI accurate for everyone?

BMI is a general screening tool, not a diagnostic one. It may overestimate body fat in athletes and muscular individuals, and underestimate it in older adults who have lost muscle mass. For a complete picture, consult a healthcare professional.

Is my data stored?

No. All calculations run in your browser. Your health information is never sent to any server or stored anywhere.

What’s a healthy BMI?

A BMI between 18.5 and 24.9 is generally considered healthy for adults. However, optimal weight varies by individual based on factors like age, muscle mass, bone density, and overall health.