BMI Calculator

Body mass index (BMI), also known as height-weight index, is a medical screening tool that uses data from height and weight measurements to estimate the amount of body fat you have. You can calculate your body mass index (BMI) online using the calculation tool below.

BMI Calculator

What is the Body Mass Index (BMI)?

The higher the BMI is as a result of the calculations, the higher the proportion of fat in the body is estimated to be. The higher the BMI, the greater the risk of health problems. For example, a person with a BMI in the "overweight" range may have a higher risk of diabetes than a person with a BMI in the "normal weight" range.

The BMI was developed by Lambert Adolphe Jacques Quetelet, a Belgian mathematician, and was originally used as a screening tool to measure and interpret the health status of groups, not individuals. In the mid-20th century, it was realised that the BMI ratio could be a guide for individual health assessment, as it could be determined with a simple calculation. This is because the body mass index (BMI) is a quick way of recognising when you are outside the normal range and when you are at risk.

How do you calculate the body mass index (BMI)?

Body weight can be easily calculated by dividing body weight by the square of height. For example, the BMI of a 1.70 tall person with a body weight of 70 kg is 24.2. A high body mass index does not necessarily mean that there is a health problem. The accuracy of the results may be affected because the following factors are not taken into account when calculating the BMI:

  • Ethnicity and genetic factors: The effects of genetic factors and ethnicity on muscle mass can lead to an incorrect calculation of body fat percentage in BMI.
  • Muscle mass: Athletes tend to have a lower fat mass. As BMI is calculated as the ratio of height to body weight, it cannot clearly predict how much of the weight is fat and how much is muscle. Even if athletes have a higher weight, their body fat percentage can be low.
  • Body type: The body mass index does not take waist circumference into account. The same BMI ratio can be achieved by measuring the weight and height of two different people with pear and apple body types. However, the person with the apple type may have a higher cardiovascular risk than the person with the pear type, as the fat content of the person with the apple type is higher in the waist.

All these factors can make the BMI result unreliable. However, BMI is a simple and quick calculation tool that is recognised by health authorities around the world. For this reason, you can regularly check your body mass index for a healthy life and get an overview of your overall health.

How high should the body mass index be?

The World Health Organisation classifies BMI results for adults over the age of 20 in 6 different ways. The World Health Organisation classifies the answer to the question of how high the body mass index (BMI) should be based on the following ratios:

  • Under 18.5: Underweight
  • 18.5 to 24.9: Normal weight
  • 25.0 to 29.9: Overweight
  • 30.0 to 34.9: Overweight grade 1
  • 35.0 to 39.9: Overweight grade 2
  • 40.0 and more: Morbidly obese people

If your result is above 24.9, this means that your weight is higher than it should be. The higher this value is, the more it can be assumed that you are overweight.

The BMI is also interpreted according to the above list for people over the age of 20. The World Health Organisation recommends that the BMI should also be used for children and adolescents. The calculation method is the same as for adults. After the calculation, the ratios are compared with the percentiles of the child's peers. The relationship between weight and height in childhood and adolescence varies according to gender and age. Therefore, the values that determine the nutritional status of persons aged 0-19 years are gender and age specific. The index for height and weight varies according to age.

What should be done after the results of the body mass index?

A high body mass index can be a harbinger of obesity and risks such as cardiovascular disease, high blood pressure, type 2 diabetes, gallstones and respiratory problems. If your BMI is too high according to the required measurements, you can start making simple changes toward a healthy lifestyle. The following suggestions can help you do this:

  • Reduce your daily calorie intake: The most basic rule for reducing body mass index and healthy weight loss is to eat fewer calories than you burn. Although daily calorie needs vary by age, gender and activity level, you can determine your daily nutritional needs with the help of a professional. Then start consuming more calories than you take in by increasing your activity level.
  • Remove convenience foods from your life: You can reduce your sodium levels by avoiding processed foods such as crisps and ready meals. At the same time, these foods contain a lot of fat or processed sugar. This can lead to weight gain.
  • Regular sleep is important: If you sleep too little, your metabolism works more slowly. This can make it difficult to burn calories, even if you exercise. At the same time, sleep controls the hormones ghrelin and leptin. Ghrelin is the hormone that signals hunger to the body, while leptin is the hormone that helps the body understand satiety. If you don't get enough sleep, your body can't release these hormones as much as it should. This leads to weight gain and increases your BMI.
  • Add cardio exercises to your daily routine: Cardio exercises help you burn excess body fat by increasing your heart rate;

What should the diet look like after a high body mass index?

If your body mass index is high, you should focus on fruit and vegetables. The Mediterranean diet, for example, which is light and healthy and helps you lose weight, can also help you lower your body mass index. In this diet, fruit and vegetables are among the staple foods. Vegetables in particular contain many nutrients that your body needs. You can also follow the advice below to help you achieve or maintain a healthy weight:

  • Choose healthy foods: You can consume mineral water by changing your habit of sugary and carbonated drinks that can lead to weight gain. Adding fresh fruit juices to mineral water will give you delicious flavours. Also, replace starchy foods such as bread, flour and rice with wholemeal products. Wholemeal products are less processed than their white counterparts and contain much more fibre and natural nutrients.
  • Eat high-fibre foods: Foods such as oats and wholemeal flour are rich in fibre. Fibre-rich foods help you stay full for a long time. At the same time, they support the digestive system and can provide you with energy.
  • Include protein in your meals: Protein provides fewer calories than carbohydrates and fat. Despite its low calorie count, it provides a long-lasting feeling of satiety. Eggs are an effective source of protein and extremely rich in minerals. If you follow a vegan diet, lentils and beans are also good sources of protein.
  • You can choose lean meat for your meals: Lean meat is one of the foods that help you lose weight because it is high in protein and low in carbohydrates.

Even if you focus on protein in your meals, you also need carbohydrates, fats, vitamins and minerals for a healthy diet. You can consume carbohydrates from healthy sources such as oats. Fats, on the other hand, help you get the omega-3 and omega-6 fatty acids you need. For this reason, you can include olive oil, which is rich in omega 3 and 6, in your diet. For vitamins and minerals, you should include vegetables, fruit, healthy herbs and salads in your meals.

How do you eat with a low body mass index?

A BMI below 18.5 means that you are "underweight". A low BMI can be just as harmful as a high BMI. If your BMI is below 18.5, you can take the following steps to gain weight in a healthy way:

  • Eat more often: If your BMI is low, you will quickly feel full. For this reason, you can increase the number of meals per day.
  • Keep moving: Exercise can create a calorie deficit. A calorie deficit does lead to weight loss, but if you switch to the right diet, you can get healthy by building muscle mass with high calorie expenditure. In addition, resistance exercises that you perform at an optimal level can help you feel more hungry as they create an energy deficit.
  • Choose rich foods: Go for wholemeal bread and pasta, which are generally part of a healthy diet. Don't neglect your protein intake from milk and dairy products. Nuts such as hazelnuts and peanuts are both plant-based sources of protein and foods that help you get healthy calories.
  • Keep your fluid consumption under control: Drinks that you drink before meals can curb your appetite. Therefore, have your drinks about 30 minutes after your meal.
  • Watch out for fat and sugar: It's okay to have a chocolate cake from time to time. However, processed sugar and fats can prevent you from eating healthy calories. Wholemeal muffins and granola bars are a good alternative to get the nutrients you need along with a high calorie content.
  • Enrich your portions: Any food you add to your portions will give you extra calories. So add things like cheese, sauce and yoghurt to the meals you prepare for yourself. This will increase the amount of calories you eat and help you gain weight healthily.

Remember that body mass index is a good tool to assess your overall health. You can calculate your BMI by dividing your weight by the square of your height from time to time to find out if you are doing well. Even if you are in the normal range, you can maintain your ideal weight by following the diet and exercise recommendations as you approach the lower or upper limits. You can find out your ideal weight on the calculating your ideal weight page.