Understanding your healthy weight: Body mass index (BMI) and waist to hip ratio (WHR)

Weighing too much or too little can have a number of consequences on your overall health.

Why a healthy weight range is important

By being above or below your healthy weight range you're increasing your chances of suffering from a number of serious health problems.

Health problems associated with being overweight include:

  • type 2 diabetes
  • stroke
  • heart disease
  • some cancers
  • issues with fertility in women
  • high blood pressure
  • osteoarthritis
  • fatty liver disease
  • kidney disease

Health problems associated with being underweight include:

  • weakened immune system
  • osteoporosis
  • anaemia
  • issues with fertility in women
  • palpitations

Understanding your healthy weight

Whether you weigh yourself once a week or are avoiding standing on the scales altogether, it's important to have an idea of your body mass index (BMI) and your waist circumference. These measurements are just a rough guide but can be beneficial in establishing what our ideal weight range may be.

Body mass index (BMI)

The BMI scale uses both your weight and height in order to calculate roughly how much body fat you have.

To calculate your BMI, you'll need to:

  1. find your weight in kilograms (kg) and the square of your height in metres
  2. divide your weight by your height

This will give you a figure to identify your healthy weight.

Your BMI will fit into one of 4 categories:

  • underweight - those with a BMI of under 18.5
  • healthy weight - those with a BMI between 18.5 and 24.9
  • overweight - those with a BMI between 25 and 29.9
  • obese - those with a BMI between 30 and 39.9
  • morbidly obese - those with a BMI of 40 or over
BMI chart
Use our chart to find out if you are over or under weight using your BMI result NHS inform

If your BMI is out with the healthy weight range (between 18.5 and 24.9) you should try to either gain or lose weight by eating a balanced diet and doing appropriate exercise.

It's important to remember that BMI isn't a suitable measurement for certain people, including:

  • children
  • pregnant women
  • athletes or those who're extremely muscular

Waist circumference

Another way to measure whether your weight might be affecting your health is to calculate your waist circumference. If you store most of your weight around your midsection (over your hips and thighs) then you could be at an increased risk of heart disease, high blood pressure and type 2 diabetes.

All you need to measure your waist circumference is a plastic or cloth measuring tape. To get a measurement:

  1. wrap the tape around your waist at the soft fleshy section at the top of your hips and bottom of your ribs - this will normally be just above your navel and the smallest section of your torso
  2. stand up straight and exhale to get an accurate reading
  3. wrap the measuring tape all the way around this section - the number where the ends of the tape meet is your waist circumference

Healthy waist circumferences are:

  • less than 37 inches for men
  • less than 32 inches for women

If you're not sure you're a healthy weight, your doctor will be happy to carry out the above measurements for you and advise you on the results.