BMI Calculator
Understand your body.
Move toward a healthier life.
Work out your Body Mass Index (BMI) from your height and weight, in metric or imperial units — then use it as one simple starting point, not a verdict.
Start with the calculatorHealth is more than a number.
Your BMI can be a useful starting point, but feeling healthy is also about movement, nutrition, sleep, energy and wellbeing — none of which fit into a single figure.
- Move Walking counts. So does dancing in the kitchen.
- Nourish Food you enjoy, most of the time.
- Rest Sleep does more than any single habit.
- Enjoy If it isn’t sustainable, it isn’t working.
Small steps add up.
How BMI is calculated
Body Mass Index divides your weight (in kilograms) by the square of your height (in metres). It’s a quick, free screening measure used worldwide, including by the NHS and CDC, to flag whether someone’s weight may be putting their health at risk.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity |
One number doesn’t tell the whole story.
BMI is a general screening tool and doesn't account for muscle mass, bone density, age, sex, or ethnicity - it isn't a diagnosis, and this is not medical advice. If you have concerns about your weight or health, speak with a doctor or registered dietitian.
Source: BMI thresholds shown above (underweight, healthy weight, overweight, obesity) follow the World Health Organization's BMI classification, also used by the NHS and CDC for adult screening.