BMI Calculator
Check your Body Mass Index (BMI) in metric or imperial units, and see whether you may be eligible for weight loss medication. BMI uses your height and weight to estimate whether your weight is in a healthy range.
Understanding your results
Under 18.5: You are considered underweight. We do not provide weight loss medication for individuals in this category.
18.5 to 24.9: You are within a healthy weight range for your height. Weight loss medication is not appropriate or necessary.
25.0 to 26.9: You are considered overweight. Weight loss medication isn't usually suitable at this BMI, but diet, activity and lifestyle changes can make a real difference.
27.0 to 29.9: You are considered overweight. You may be eligible for weight loss medication if you also have a weight-related health condition, such as type 2 diabetes or high blood pressure.
30.0 and above: You fall into the obesity category. You may be eligible for weight loss medication, subject to a medical assessment.
BMI and weight loss medication: common questions
What BMI do you need for weight loss medication in the UK?
Weight loss medications licensed in the UK are generally prescribed for adults with a BMI of 30 or more, or a BMI of 27 or more who also have at least one weight-related health condition. BMI alone doesn't decide whether treatment is right for you – a clinician must always review your medical history first.
Which weight-related health conditions count?
Examples include type 2 diabetes or prediabetes, high blood pressure, raised cholesterol, obstructive sleep apnoea and heart disease. You'll be asked about any conditions you have during your assessment.
Are BMI thresholds different depending on ethnicity?
Yes. People of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background are at higher risk of conditions such as type 2 diabetes at a lower BMI. For these groups, NICE recommends lower thresholds: a BMI of 23 or more indicates overweight, and 27.5 or more indicates obesity. We take this into account when assessing you.
How accurate is BMI?
BMI is a useful starting point, but it can't tell the difference between fat, muscle and bone, or show where fat is stored. Very muscular people can have a high BMI without carrying excess fat. Measuring your waist adds useful information: NICE advises keeping your waist measurement to less than half your height. Adult BMI doesn't apply during pregnancy.
Who shouldn't use weight loss medication?
It isn't suitable for everyone – for example, if you're under 18, pregnant, trying to get pregnant or breastfeeding, or have certain medical conditions. We check your medical history and current medicines before recommending any treatment.
What happens if I might be eligible?
Start our online assessment. You'll answer questions about your health, verify your identity, and our doctor will review everything. If treatment is suitable, we'll create a personalised plan, arrange for your medication to be delivered from a partner UK pharmacy, and support you with regular check-ins.