Body mass index is a simple calculation that compares your weight to your height to estimate whether you’re in a healthy range. Our free BMI calculator uses the standard medical formula, then places your result into the recognised categories — underweight, healthy weight, overweight or obese — so the number actually means something. It’s a widely used screening figure, which is why doctors, gyms and health sites rely on it as a quick first check.

Keep in mind that BMI is a general guide and doesn’t account for muscle, age or build, so it’s best treated as a starting point rather than a full health verdict. For tracking other goals, our free tools can help too — try the Salary Calculator or explore the full set on our tools page.