BMI Calculator
Calculate your Body Mass Index using your age, height and weight, then review your indicative BMI category and healthy weight range.
Enter your details
Check your BMI instantly
Choose your preferred units and enter accurate measurements for a more useful result.
Your result will appear here
Complete the fields and select “Calculate my BMI” to view your score, category and indicative healthy weight range.
Your BMI score
Understanding the result
What does BMI measure?
BMI is a screening calculation based on weight relative to height. It can help identify broad weight categories, but it does not directly measure body fat, muscle mass or overall health.
BMI for men
Adult BMI thresholds are interpreted using the same general categories for men and women. Men with high muscle mass may receive a higher BMI even when body-fat levels are not high.
BMI for women
The adult BMI calculation is the same for women. Pregnancy, age, hormonal changes and differences in body composition can affect how an individual result should be interpreted.
BMI by age
Children and teenagers require age- and sex-specific percentile assessment. In older adults, muscle loss and body composition changes can reduce the usefulness of BMI as a standalone indicator.
Adult reference guide
BMI category chart
The following ranges are commonly used as a general screening reference for adults aged 20 and above.
Visual adult BMI chart
Use the coloured scale to understand where an adult BMI score sits. After calculation, your BMI marker will appear automatically on this chart.
| BMI range | Category | General interpretation |
|---|---|---|
| Below 18.5 | Underweight | Weight may be low relative to height. |
| 18.5–24.9 | Healthy weight | Falls within the commonly referenced adult range. |
| 25.0–29.9 | Overweight | Weight is above the commonly referenced adult range. |
| 30.0 and above | Obesity | A clinical assessment may provide more meaningful context. |
Height and weight reference
BMI chart
Cross-reference your height with your weight in kilograms to read an approximate BMI directly. After using the calculator, the closest matching cell is highlighted automatically.
| Height |
|---|
*BMI values are rounded to the nearest whole number. The highlighted cell uses the closest available height and weight in this reference chart. Scroll sideways on mobile to view all columns.
Important context
How BMI changes across life stages
The same calculation can require different interpretation depending on age, growth, pregnancy, muscle mass and medical context.
Children and teenagers
For people aged 2–19, the BMI number should be assessed against age- and sex-specific growth percentiles. Adult BMI categories should not be used to classify a child or teenager.
Older adults
Age-related muscle loss can change the relationship between BMI and body composition. Strength, mobility, waist circumference, diet and clinical history can add valuable context.
Factors BMI does not directly measure
- Body-fat percentage or where fat is stored
- Muscle mass, bone density or athletic build
- Pregnancy-related changes
- Blood pressure, blood sugar, cholesterol or nutritional status
Frequently asked questions