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Why We're Different

  • Access to a team of specialist bariatric nurses – expert medical advice and regular medical reviews
  • Access to the hospital out of hours service
  • Access to a dietician - expert nutritional advice on making the most of the procedure you have chosen to have
  • 2 x-ray adjustments and up to 6 clinical adjustments
  • Access to your surgeon as clinically indicated
  • Access to support groups for patients
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How is BMI calculated ?

Body mass index (BMI) is a measurement of a person's weight in relation to their height. It offers an inexpensive and simple method of categorising people according to their BMI value so that we can screen people’s weight category and indicate their potential risk for health conditions.

What is a bmi calculation? 

There are two BMI calculation formulas to calculate BMI depending whether you’re using metric or imperial measurements. BMI calculation formula

How is BMI calculated ?

BMI = Weight (kg) / Height (m)²  

To calculate BMI kg the metric formula is your weight in kilograms divided by your height in meters squared.

For example

If you are 175cm (1.75m) in height and 75kg in weight, you can calculate your BMI as follows:

75kg / (1.75m²) = 24.49kg/m²

Imperial BMI formula

BMI = [Weight (lbs) / Height (inches)²] x 703

The imperial BMI formula is your weight in pounds (lbs) divided by your height in inches, squared and then you multiply this figure by a conversion factor of 703.

For example

If you’re 5’5” (65”) in height and 150lbs in weight, you would calculate your BMI as follows:

[150lbs / (65 inches²)] x 703 = 24.96

BMI weight categories

Based on your height and weight, you will be assigned to one of the following weight categories:

Underweight - BMI less than 18.5

Normal healthy weight - BMI between 18.5 and 24.9

Overweight - BMI between 25.0 and 29.9

Obese - BMI between 30.0 and 39.9

Morbidly obese – BMI 40.0 and above

Weight categories can be further classified. The table below is from the WHO and shows the international classification of adult underweight, overweight and obesity according to BMI¹



Principal cut-off points

Additional cut-off points




Severe thinness



Moderate thinness

16.00 - 16.99

16.00 - 16.99

Mild thinness

17.00 - 18.49

17.00 - 18.49

Normal range

18.50 - 24.99

18.50 - 22.99

23.00 - 24.99





25.00 - 29.99

25.00 - 27.49

27.50 - 29.99




Obese class I

30.00 - 34.99

30.00 - 32.49

32.50 - 34.99

Obese class II

35.00 - 39.99

35.00 - 37.49

37.50 - 39.99

Obese class III



Online BMI calculator

For ease, you can use our automated BMI calculator. Simply tap in your weight and height details in either metric or imperial measurements and this tool will calculate your BMI. It also offers a useful reference of the BMI weight categories and their corresponding BMI values.

How to use BMI figures

BMI is a screening tool of your body fatness and your health. The higher your BMI the greater the indication of high body fatness and, excess body fat is known to be linked to both current and future morbidity.

If your BMI figure indicates you are a normal healthy weight that’s great news. You may want to monitor your BMI on a regular basis to keep abreast and check that you remain in this category.

If you have a high BMI and you fall into the overweight or obese categories, you should arrange an appointment with your doctor who may recommend further diagnostic tests to explore any health risks. These diagnostic tests might include: skinfold thickness and waist measurements, diet and physical activity evaluations, family history and, other appropriate health screenings. Your doctor may also offer lifestyle and diet advice to help lower your BMI.

If you have a low BMI and you are classified as underweight, then you may want to review your diet with a view to gaining some weight. Your doctor will be able to give you advice.

Limitations of BMI

Although there is a correlation between BMI and body fatness, there are limitations of BMI that have been greatly discussed in the medical field.  These include

  • Athletes and body builders who have a high proportion of muscle (muscle weighs more than fat) are categorised with a high BMI
  • There are height and weight ratio differences between races.
  • Age and sex are not taken into account.  BMI for Women tend to have more body fat than BMI for men of equal BMI and older people tend to have more body fat than younger people with the same BMI
  • BMI also does not account for pregnant or lactating women and, children and teenagers who are still growing and are not yet physically mature.

Health consequences of obesity in adults

Research has shown that people whose BMI falls into the overweight or obese BMI categories are more likely to experience health problems associated with excess weight.

These diseases and health conditions include: high blood pressure (hypertension), type 2 diabetes, coronary heart disease (CHD), stroke, musculo-skeletal problems, sleep apnoea and breathing problems and some cancers. Many of these are often preventable by engaging in a healthy and active lifestyle.

Are You Eligible

Are You Eligible?

Weight loss surgery is performed to control weight. There are two basic ways that weight loss surgery works to help patients lose weight and improve both physical and lifestyle conditions.

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Benefits of Surgery

Weight loss will improve the physical and lifestyle conditions associated with being overweight.

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How Are We Different

How Are We Different?

We know how hard the fight with obesity is...members of our team have had the surgery themselves and therefore our multidisciplinary team can talk from real life experience about weight loss surgery.

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Your Aftercare

Your Aftercare

We invest heavily in resources for our post operative care. Feel safe in the hands of our specialist multi disciplinary team.

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Benefits Of Surgery

Frequently Asked Questions

Weight loss surgery is the first part of a long process, aftercare is the key to success. Support is ultimately the one part of the journey that truly does make a real difference.

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Weight Loss Prices

Weight Loss Prices

Weight loss surgery is the first part of a long process, aftercare is the key to success. Support is ultimately the one part of the journey that truly does make a real difference.

Find Out More

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Talk to one of our dedicated weight loss enquiry handlers

Our specialist enquiry handlers will be able to help you with any questions you may have!