How high is my BMI? Calculate and interpret your value in 2026

You calculate your BMI by dividing your weight in kilograms by your height in metres squared. A BMI between 18.5 and 24.9 counts as a healthy weight for adults. If your value is higher or lower, that is a first signal to take a closer look at your lifestyle. In this article you will learn how to work out your BMI, what the result per category means, and which follow-up steps you can take.

What is BMI and why do you measure it?

BMI stands for Body Mass Index and was developed in the nineteenth century by the Belgian mathematician Adolphe Quetelet. Originally it was a statistical tool for population research, but today doctors, dietitians and sports coaches use it as a quick first indicator of someone’s weight class.

The idea is simple: BMI sets your weight against your height and produces a number that indicates whether your weight is in proportion to your build. That makes it a practical starting point for a conversation about health, but it is explicitly not a complete diagnosis.

Worldwide, the World Health Organization uses BMI as a measure to monitor trends around overweight and obesity, as set out in the source: WHO guidelines. In the Netherlands, the RIVM processes the population’s BMI figures into its annual reports on public health. Understanding how your BMI is established is the first step towards insight into your own health.

How do you calculate your BMI yourself?

The formula: weight divided by height squared

The calculation needs just two pieces of data: your weight in kilograms and your height in metres. The formula is: BMI = weight (kg) / height (m)². You multiply your height by itself and divide your weight by that result. All you need is a scale and a tape measure.

Suppose you weigh 80 kilograms and you are 1.75 metres tall. The calculation: 1.75 × 1.75 = 3.0625 and then: 80 / 3.0625 = 26.1. Your BMI in that case is 26.1.

Worked example for an adult

Take a second person: 65 kilograms, 1.65 metres tall. The calculation: 1.65 × 1.65 = 2.7225. Then: 65 / 2.7225 = 23.9. That falls neatly within the healthy range of 18.5 to 24.9.

If you want to make it easier on yourself, there are online BMI calculators that do the maths for you. Type in your weight and height and the result appears immediately. Bear in mind that most standard calculators are set up for adults. For children, teenagers and older adults, different reference values apply — more on this further down the article.

BMI table: what does your result mean?

The World Health Organization divides adults into six weight categories based on their BMI. The table below provides an overview of the cut-offs and what they mean for your health.

With a BMI in the overweight category, the risk of type 2 diabetes, cardiovascular disease and joint complaints increases. The higher the BMI, the greater that risk. With obesity class 3, professional medical advice is always recommended.

The other way around applies too: a BMI under 18.5 is not carefree either. Underweight raises the chance of bone loss, chronic fatigue and a weakened immune system. The table gives a first orientation, but says little about your body composition. Further on you will read why that is an important point.

BMI per age and sex

BMI is not the same measure for everyone. Age and sex influence how to interpret the result, and it is good to know those nuances before drawing conclusions.

BMI for women

Women naturally have a higher body fat percentage than men, even at the same BMI value. Doctors use the same cut-offs for both sexes, but sex plays a role in interpretation. A woman with a BMI of 24 may have a fine body composition, while a man with the same value usually has more muscle mass and less fat. Women who land just over 25 do not automatically need to view that as problematic.

BMI in older adults from age 70

For those over 70, different considerations apply. Research shows that a BMI between 25 and 27 in older adults may actually be protective. With aging you lose muscle mass and bone density declines. A small weight reserve then provides a buffer during illness or recovery from a procedure. Always discuss your result with a GP for tailored personal advice.

BMI in children and teenagers

For children and teenagers, the standard BMI table does not work. They are assessed using growth curves that take age and sex into account. A ten-year-old with a BMI of 20 can have either a healthy weight or overweight, depending on the comparison with peers. For children, always use a special children’s BMI calculator or consult the youth doctor.

The limitations of BMI: why the meter does not say everything

BMI only measures the ratio between weight and height. That is useful as a first indicator, but the number has clear limits you should know.

A muscular athlete can have a BMI of 27 and still be in great health, while someone with a ‘normal’ BMI may have little muscle mass and a lot of fat mass. That combination, popularly called ‘skinny fat’, carries health risks that BMI completely conceals.

What is more, BMI does not look at the distribution of fat over your body. Abdominal fat is medically more dangerous than fat on the hips or thighs, because it sits around your organs. Someone with a lot of belly fat and a BMI of 25 has a higher risk than someone with that same BMI but a more favourable fat distribution.

Finally, the cut-offs are largely based on data from Western European men. For people with an Asian or African background, the risk thresholds may lie elsewhere. So always use BMI together with other measures.

Measuring waist circumference as a supplement

Waist circumference is a valuable addition to your BMI, because it says something directly about the amount of belly fat. Belly fat sits around the organs and raises the risk of cardiovascular disease, as confirmed in Hartstichting research.

You measure it as follows: stand up straight, breathe out normally and place a tape measure horizontally around your middle at the level of your navel. Make sure the tape is snug but not tight.

For men, a circumference above 102 centimetres counts as risky; for women the cut-off is 88 centimetres. If your waist circumference is above that line, even when your BMI falls in the healthy range, then a conversation with your GP is a sensible step. The combination of BMI and waist circumference gives a much more complete picture of your health risk than the number on the scale alone.

What to do with a BMI that is too high or too low?

A deviating BMI is a signal, not a verdict. There are concrete steps you can take, whether your value is too high or too low.

With overweight or obesity, a combination of better nutrition and more movement helps the most. The source: Voedingscentrum advises a varied diet with plenty of vegetables, fruit, wholegrain products and sufficient protein, and as few processed products and sugary drinks as possible. Combine that with at least 150 minutes of moderate movement per week: think of walking, cycling or training at a gym.

If you cannot manage on your own, a GP or dietitian is the right next step. A dietitian draws up a personal nutrition plan, tailored to your goals, daily rhythm and any medical situation.

With underweight, professional guidance is just as important. Have a possible underlying cause, such as a thyroid disorder or eating disorder, ruled out by your GP. Self-diagnosis falls short here.

Exercising with overweight: how Gymsearch helps you

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Gyms with personal coaching

Personal training is ideal if you want to work in a focused and responsible way on weight loss. Chains like Basic-Fit, SportCity and Anytime Fitness have certified trainers specialised in weight management. On compare gyms you can compare personal trainer rates in your area, so you know exactly what to expect and there are no surprises.

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Conclusion and when to consult a doctor

BMI is a useful starting point for placing your weight in context, but it is not a complete diagnosis. Use the value as an orientation and combine it with your waist circumference, your lifestyle and possibly a conversation with your GP or dietitian.

Note: this article contains general information and does not replace medical advice. In doubt about your weight, eating pattern or health? Always consult a doctor or certified dietitian. BMI is a guideline, not a diagnosis.