BMI calculator

Use our online calculator to check your body mass index. BMI can help determine if you’re within a healthy weight range for your height.

How tall are you?

Feet (ft)
Inches (in)

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What do you weigh?

Stone (st)
Pounds (lbs)

Switch to kilograms

What is BMI?


Calculating your BMI is a simple way to check if your weight is healthy for your height. It can help you understand if you are classified as overweight and provide a starting point for how much weight you might want to lose.

Remember, BMI is just a quick guide. It doesn’t look at other things that can affect your weight, like muscle mass, fat mass, bone density, or water weight. For example, athletes might have a high BMI due to their muscle mass rather than body fat. Older people might have a lower BMI despite having more body fat, due to a loss of muscle mass. BMI may also underestimate health risks for some ethnic groups or overestimate for others.

For a clearer picture of your health, you might also consider other measures like your waist size or waist-to-hip ratio, as carrying extra fat around your waist can increase health risks.

What are the BMI ranges?


For most adults, if your BMI is:

  • below 18.5 you're in the underweight range
  • 18.5 to 24.9 you're in the healthy weight range
  • 25 to 29.9 you're in the overweight range
  • 30 to 39.9 you're in the obese range
  • 40 or above you're in the severely obese range

Should I be concerned with a high BMI?


A higher BMI increases your risk of health problems like diabetes, gallstones, high blood pressure, heart disease, and some types of cancer. If your BMI is over 25, it may be worth considering weight loss to lower your risk of obesity-related conditions and improve your overall health.

How can I lose weight?


If your BMI is over 27 and you have weight related co-morbidities such as pre-diabetes, diabetes or heart disease, you may be eligible for prescription weight loss treatments. These can help you lose up to 20.9% of your body weight and are substantially more effective than diet and exercise alone. Visit our weight loss page to learn more.