BMI Calculator (UK)
Calculate your Body Mass Index (BMI) in metric or imperial units. WHO categories, healthy range, and what your number actually means.
Understanding Body Mass Index (BMI)
Body Mass Index (BMI) is a screening tool used to assess whether an individual is at a healthy weight for their height. It is calculated by dividing weight in kilograms by height squared in meters, or via imperial units by multiplying weight in pounds by 703 and dividing by height squared in inches.
BMI categories help classify adults into underweight (under 18.5), normal weight (18.5 to 24.9), overweight (25 to 29.9), and obese (30 and above). Keeping your BMI in a healthy range reduces the risk of serious health conditions, including Type 2 diabetes, high blood pressure, and cardiovascular disease.
However, BMI has several notable limitations. It does not measure body fat directly and cannot distinguish between weight from fat versus weight from muscle. For example, athletes and bodybuilders with high muscle mass may be classified as overweight or obese according to BMI, despite having low body fat percentages. It is best used alongside other metrics like body fat percentage and waist circumference.
Frequently Asked Questions
Q: What is a healthy BMI range?
A healthy BMI for adults is between 18.5 and 24.9. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or higher is obese.
Q: Is BMI accurate for muscular individuals?
No, BMI does not distinguish between muscle and fat. Muscular individuals may have a high BMI but very low body fat, meaning their health risk is not elevated.