For adults aged 18+. Not suitable for children, pregnant women, or athletes. Consult your GP for medical advice.
How to use
- Select metric (kg and cm) or imperial (stone/lbs and feet/inches) input.
- Enter your weight and height.
- Your BMI score and NHS weight category appear instantly.
About this tool
Body Mass Index (BMI) is a measure calculated from your height and weight that is used as a screening tool for weight-related health risks. The NHS recognises four categories: underweight (BMI below 18.5), healthy weight (18.5–24.9), overweight (25–29.9), and obese (30 and above). BMI is a useful population-level indicator, but it has well-documented limitations as a measure for individuals: it does not account for muscle mass (athletes often show a high BMI despite being very lean), it does not distinguish between body fat and lean tissue, and the healthy ranges are less accurate for older adults and some ethnic backgrounds. Always consult your GP for personal health and weight advice rather than relying on BMI alone.
For adults aged 18 and over only. Not suitable for children, pregnant women, or athletes. Consult your GP for medical advice.