VitalisBMI Calculator
Calculate your body mass index and see where it falls against the standard healthy-weight range.
About the BMI calculation
Body mass index (BMI) is calculated as weight in kilograms divided by height in metres squared. It's a quick, population-level screening measure - doctors and researchers use it because it's cheap and easy to calculate from just two numbers, not because it's a precise measure of body fat.
- <18.5 Underweight - may indicate insufficient energy intake.
- 18.5–24.9 Healthy range for most adults.
- 25–29.9 Overweight - worth discussing with a clinician if paired with other risk factors.
- 30+ Obesity range, associated with higher health risk on average.
Frequently asked questions
What is a healthy BMI range for adults?
For most adults, a BMI between 18.5 and 24.9 is classed as the healthy weight range. Below 18.5 is considered underweight, 25 to 29.9 is overweight, and 30 or above falls in the obesity range.
Is BMI accurate for everyone?
BMI is a screening measure based on height and weight only, so it doesn't distinguish muscle from fat. It can overestimate body fat in muscular people and underestimate it in older adults who've lost muscle mass - it's a starting point, not a diagnosis.
How is BMI calculated?
BMI is weight in kilograms divided by height in metres squared (kg/m²). In imperial units, it's weight in pounds divided by height in inches squared, multiplied by 703.