FOR ADULTS AGED 18 AND OVER
Understand your BMI.
Enter your height and weight to calculate your body mass index
and see what your result means.
Calculate your BMI
Choose your units, then add your measurements.
YOUR RESULT
Your body mass index
Your BMI rounds to a category boundary. The category uses the value before rounding.
Healthy-weight range for your height
An approximate reference range using BMI 18.5–24.9, not a personal weight target.
This uses standard adult categories without adjustments for ethnic background. BMI alone cannot determine your health. This result is not personalised medical advice. Read the limitations.
UNDERSTANDING THE RESULT
What does your BMI mean?
BMI is your weight in kilograms divided by your height in metres squared. For example, 70 kg at 1.70 m gives a BMI of 24.2.
Standard adult BMI categories
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Healthy weight |
| 25.0–29.9 | Overweight |
| 30.0 and above | Obesity |
These familiar ranges are shown to one decimal. Categories use the unrounded BMI, with cut-offs at 18.5, 25 and 30.
A number with limitations
BMI does not distinguish between muscle and fat. Someone with a lot of muscle may have a high BMI without having a lot of body fat.
Health risks can occur at lower BMI levels for people from Asian, Black African, African–Caribbean and Middle Eastern backgrounds. This calculator does not adjust its categories for ethnic background.
Your medical history and other measurements also matter. If you are concerned about your weight or your result, speak to a GP or pharmacist.
Further guidance
Read the NHS adult BMI guidance and calculator for more tailored interpretation, or learn about BMI and its limitations on the NHS website.