Body mass index (BMI) calculator – Are you overweight?

BMI Calc.:

Your Weight:
Your Height:

N.B. For an explanation of Body Mass Index and a discussion about its limitations and alternative weight measurement calculations see the section below the action plans. If you are here to ask “am I overweight?”, please take your height and weight measurements and use the calculator or chart before asking in the comments below – thanks!

BMI Action Plans:

Below 18.5 Underweight

If your BMI is less that 18.5 it is a strong indicator that you are underweight. To put on weight the only healthy method is to increase calorie intake and exercise more. A low body weight indicated a lack of healthy muscle tissue. Ensure that your diet is well balanced and consider increase protein intake to aid muscle growth.

Start exercising a few times a week with a combination of cardio workouts (running, swimming, sports), bodyweight circuit training workouts and fitness classes.

You need to eat more, workout more and build some muscle. See also the articles about protein and weight training.

18.5 – 24.9 Normal

A BMI of 18.5 to 24.9 indicated that you are at a healthy weight. Well done, you are doing just fine. However, you may not be healthy, look to improve your diet and take regular exercise.

A healthy body weight is not always a fit and healthy body. If you are not fit and consuming too few calories then you may still be lacking in some essential nutrition as well as setting yourself up for longer term problems due to inactivity.

25.0 – 29.9 Overweight

A BMI of 25 to 29.9 suggests that you are overweight and are probably developing some excess fat. Unless you have built up a lot of muscle mass in recent years then there is a very good change that you need change your diet and exercise more to start burning off excess fat.

To lose weight you need to combine healthy diet and regular fitness activities. You do not need to join a gym although it can help. We have many suggestions for home fitness workouts and also advice on how to eat healthy. You may also want to consider following a weight loss plan. If you are looking for an effective diet solution then take a look at our Low GI Diet eBook.

30.0 + Obese

A BMI of over 30 indicates that you are obese. You really have to make some changes. You need to take urgent action to start losing fat and improving your fitness. Total lifestyle change is required. If you have not exercised for a long time then start easy with our walking for fitness plan and then move on to more intensive forms of fitness training.

Also read up on the basics of a healthy diet and start making changes to your diet to improve quality and reduce quantity. Also consider a low GI diet which will help you to control blood sugars and lose weight – Low GI Diet eBook.

Limitations of BMI

What does it mean to be overweight? Can we really calculate how overweight a person is? There are a few methods to determine whether or not you are overweight and while none are perfect they do all provide a good indication of whether or not you are healthy.

Body Mass Index tool is still the most commonly used calculation because it is so easy to measure – you just need to know your height and weight.

However, BMI does not take into consideration muscle:fat ratios, so male athletes can sometimes appear overweight on the scale while women with very little muscle mass may appear a “normal” weight when they are actually carrying too much fat.

For example, Arnold Schwarzenegger’s BMI is around 35 – based on a height of 178 cm and mass of 113 kg. He is certainly not obese or overweight.

Health professionals also use waist measurement, including waist-to-hip ratio, to determine if a person is carrying too much fat.

However, for simplicity we shall provide you with a body mass index calculator (just below this explanation).

We have also added a chart to provide a better visualization of obesity levels. At the end of the article there are also note on genetic / racial variations that should be considered.

What Is Body Mass Index (BMI)?

Body mass index (BMI) is a statistical measure of the weight of a person scaled according to height. It is a guide to how overweight or underweight a person is, but it should not be used in isolation to diagnose a weight problem.

While it can give a good answer to your question “Am I Overweight?“, it cannot provide a totally accurate answer is some circumstances – read below to learn more.

Many bodybuilders and athletes would be considered overweight according to the BMI calculation, as BMI does not take into account muscle mass, just total mass. As muscle is denser that fat, very muscular people can show a high BMI even though they are of a healthy weight.

It is generally considered that waist circumference is a better measure of how overweight a person is.

So to be healthy you really need to try to lose your excess fat and get a flatter stomach, or at least get your waist below 36 inches. However, BMI is still a good indication of whether or not you are overweight.

BMI Chart

The chart below provides a visual guide to BMI. Draw a line from your weight (in pounds at the top or kilos at the bottom) to your height (meters on the left or feet/inches on the right) and where the lines cross is your BMI. If you are in the yellow zone you are a healthy weight.

BMI (Body Mass Index) chart

Please see below for some International variations on this scale and updated sub-categories from the World Health Organization.

World Health Organization New BMI Classification

The WHO have now provided more detailed classifications for BMI.

The International Classification of adult underweight, overweight and obesity according to BMI

Classification BMI(kg/m2)
Principal cut-off points Additional cut-off points
Underweight <18.50 <18.50
     Severe thinness <16.00 <16.00
     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
Overweight ≥25.00 ≥25.00
     Pre-obese 25.00 – 29.99 25.00 – 27.49
27.50 – 29.99
     Obese ≥30.00 ≥30.00
          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 ≥40.00 ≥40.00

Source: Adapted from WHO, 1995, WHO, 2000 and WHO 2004.

Class 3 Obese is more commonly known as morbidly obese. When someone reaches a BMI of over 40 it becomes very likely that they will develop chronic health conditions such as Type 2 Diabetes and heart disease, plus also suffer from reduced mobility and a much poorer quality of life.

Many Class 3 individuals become house bound and suffer from depression which makes changes lifestyle and dietary habits next to impossible.

International BMI Variations

Many countries have changed the scale to suit the demographics of their people. All units in kg/m2.

Japan and Hong Kong

Japan and Hong Kong have lowered the thresholds for being overweight and obese as follows:

  • Normal: 18.5 to 22.9 
  • Overweight: 23.0 to 24.9 
  • Obese 25.0: above 


Singapore has added an additional category to classify the very underweight – Emaciation. They also make a BMI of over 40 officially morbidly obese;

  • Emaciation: 14.9 or less
  • Underweight: 15 to 18.4
  • Normal: 18.5 to 22.9
  • Overweight: 23 to 27.5
  • Obese: 27.6 to 40
  • Morbidly Obese: greater than 40

References and Further Resources on BMI

  • BMI classification – World Health Organisation.
  • “Big fat beat up” by Lousie Staley. IPA Review, Institute of Public Affairs (pdf file).
  • “Adjusting athletes’ body mass index to better reflect adiposity in epidemiological research.” by Nevill AM, Winter EM, Ingham S, Watts A, Metsios GS, Stewart AD. Published in Journal of Sports Science. 2010;28(9):1009-16. Abstract.
  • Know Your Risks – Singapore Health Promotion Board.
  • “The paradox of low body mass index and high body fat percentage among Chinese, Malays and Indians in Singapore” by Deurenberg-Yap M, Schmidt G, van Staveren WA, Deurenberg P. Published in Int J Obes Relat Metab Disord. 2000 Aug;24(8):1011-7. Abstract.
  • “Overweight Japanese with body mass indexes of 23.0-24.9 have higher risks for obesity-associated disorders: a comparison of Japanese and Mongolians.” by Shiwaku K, Anuurad E, Enkhmaa B, Nogi A, Kitajima K, Shimono K, Yamane Y, Oyunsuren T.. Published in Int J Obes Relat Metab Disord. 2004 Jan;28(1):152-8. Abstract.

213 Comments on “Body mass index (BMI) calculator – Are you overweight?”

  1. Hi Rin, no you are not fat at all. Your BMI is 19.1, which is the lower end of normal. Start getting more active, take up a sport, and eat healthy foods.

  2. Hi I’m Jay 29 yr male 5ft 9inc and weigh 222 pounds, I just started the gym what should I do to look like a gladiator I want to look fit but solid and what should my meals be like and what should I eat any ideas ? Also what should my weight really be ? Thanks

  3. Hi Jay, to be within the right range for your height, you should weigh between 125 lbs / 56.6 kg and 169 lbs / 76.6 kg.

    To get a body like a gladiator you need to train like one! Martial arts would be the best way in the modern day. Kickboxing generally provides one of the best workouts because fighters train for competition and fitness is of vital importance. You also need to use weights and get plenty of cardio to burn the fat off.

    You have a lot of weight to lose but it is certainly possible. As for diet, a lean, low Gi diet is needed. You have probably developed some poor eating habits; cutting out ALL junk food is the only way to drop a lot of weight and get fit quickly.

  4. Hi, my name is Rob, I am 38 years old, I am 173 cm and 105 kg, I was 143 kg 6 months ago, when I was about 16 years old I was 95 kg and was by no means over weight, I used to play all types of sports and was in very good shape. I realise this page has the best intentions to help people but I think you should put the statement you make about this calculation being a guide at the top of the page in bold letters, because there would be a lot of people come to this page do the calculations and think that they are overweight when they are not. Thank you.

  5. Hi Rob, immediately below the calculator we mention this and further down the page there is a discussion of its limitations. However, most of those limitations are related to muscle mass in bodybuilders and other athletes and generally these people are not using BMI to determine if they might have a weight problem.

    Arnold Schwarzenegger’s BMI is also around 35 (based on 178 cm and 113 kg).

    Physical examination of fat levels using callipers is better, but not so easy to calculate.

  6. Hi.i m nijhum my height 4fit 10 n my weight 66kg.but i do not want this.i think if my body weight was 50.i will feel i want know how to lossing my weight without excersize.plz ans me.told me naturally food or tablet.ok

  7. Hi Nijhum, are you unable to exercise? If you can walk, you can exercise. And for a healthy body you need regular exercise.

    50 kg is certainly a good weight to aim for. To achieve this you should aim to lose 0.5 kg a week for the next 32 weeks. This is the safest and most effective way to lose weight. You should be able to do this by reducing your daily calorie intake.

    The average young woman needs around 2100 Calories a day and to lose 0.5 kg a week you need a daily calorie deficit of 500 Calories. So eat no more than 1600 Calories a day, and try to do some exercise, even if just walking further every day. When you are walking nobody knows that you are exercising.

    Eat 3 meals a day but reduce two to very small meals. Stop all snacks and try to stop eating bread and baked foods. Also eat only a little rice – rice on the plate is often energy we do not need.

  8. Hi Aida, you have come to the right place!

    Enter your height and weight into the calculator above or give your details to me and we will tell you.

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