BMI Calculator
Calculate your Body Mass Index to understand your weight status and health risks.
Check Your Body Mass Index
BMI is a simple measure using your height and weight to work out if your weight is healthy
Understanding Body Mass Index (BMI)
What is BMI?
Body Mass Index (BMI) is a numerical value calculated from your weight and height. It's a useful screening tool to categorize weight status and identify potential health risks associated with being underweight, overweight, or obese.
BMI Formula
- Metric: BMI = weight (kg) / height (m)²
- Imperial: BMI = (weight (lbs) / height (in)²) x 703
For example, a person who is 1.70m tall and weighs 70kg has a BMI of 70 / (1.70)² = 24.2
BMI Categories
- Underweight: BMI less than 18.5
- Normal: BMI 18.5 to 24.9
- Overweight: BMI 25 to 29.9
- Obese: BMI 30 or greater
Limitations of BMI
- Doesn't distinguish between muscle and fat mass
- May overestimate body fat in athletes
- May underestimate body fat in elderly
- Doesn't account for fat distribution
- Not suitable for pregnant women
BMI Prime
BMI Prime is the ratio of your BMI to the upper limit of normal BMI (25). A BMI Prime of 1.0 means you're at the upper limit of normal weight. Values below 1.0 indicate underweight or normal, while values above 1.0 indicate overweight or obese.
When to Consult a Doctor
- BMI is significantly outside the normal range
- Difficulty maintaining a healthy weight
- Experiencing weight-related health issues
- Planning significant dietary changes