Calculate your Body Mass Index instantly. Find out if you are underweight, normal weight, overweight, or obese based on your height and weight.
This tool calculates your Body Mass Index (BMI), a widely used screening measure that estimates whether your weight is in a healthy range relative to your height. BMI is used by healthcare providers as an initial screening tool, though it doesn't directly measure body fat.
BMI = Weight (kg) ÷ Height (m)². In imperial units: BMI = (Weight (lb) ÷ Height (in)²) × 703. Standard categories: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25–29.9), Obese (30 and above).
Enter your height and weight, and the calculator returns your BMI value along with your weight category.
Example: A person who is 1.70 m tall and weighs 65 kg has a BMI of 65 ÷ 1.70² ≈ 22.5, which falls in the "normal weight" category.
Is BMI an accurate measure of body fat? Not directly — BMI doesn't distinguish between muscle and fat mass, so very muscular individuals may show a higher BMI despite having low body fat, while it can also underestimate fat levels in some other individuals. It remains useful as a quick, low-cost general screening tool.
Why is BMI still widely used despite its limitations? It's simple, inexpensive, and correlates reasonably well with health risk at a population level, making it a practical first-pass screening tool, even though more precise methods exist for individual body composition assessment.
Does BMI apply the same way to children as adults? No, children and teens use age- and sex-specific BMI percentiles rather than the fixed adult categories, since healthy body composition changes significantly throughout growth and development.
Are there different healthy BMI ranges for different ethnicities? Some health organizations recommend adjusted BMI thresholds for certain populations (such as lower cutoffs for some Asian populations), since research has shown health risk can begin at somewhat different BMI levels across different groups.
What should I do if my BMI falls outside the "normal" range? Consider it a starting point for a broader conversation with a healthcare provider, who can assess your health more completely using additional factors like waist circumference, body composition, and overall lifestyle, rather than relying on BMI alone.