BMI Calculator
Check BMI using cm, meters, feet, kg, lb, or stone.
How to check BMI online
Use this free BMI calculator online to check body mass index from height and weight. The page uses the WHO formula: weight in kilograms divided by height in metres squared.
Adult categories: under 18.5 underweight, 18.5 to 24.9 normal, 25 to 29.9 overweight, 30 and above obese. BMI is a screening number, not a diagnosis. Athletes and older adults may need extra context from a clinician.
No account needed. Choose height in centimeters, meters, feet and inches, or inches. Choose weight in kilograms, pounds, or stone. Mix units if that is how you know your numbers, then click Calculate BMI.
BMI calculator FAQ
A BMI between 18.5 and 24.9 is generally considered a healthy weight range for most adults.
Height: centimeters, meters, feet and inches, or inches. Weight: kilograms, pounds, stone, or stone and pounds. You can mix them, for example 5 ft 10 in and 75 kg.
Not always. BMI can overestimate body fat in muscular people and underestimate it in older adults who have lost muscle mass. It is a general screening tool, not a full health assessment.
Checking every few months is enough for most people tracking general health trends over time.