WhatsApp

BMI Calculator: Check Your Body Mass Index and What It Means

Calculate your BMI

For adults aged 20 and over. Children and teenagers aged 2 to 19 need the CDC calculator for children and teens, because their results are read against age and sex.

Units

BMI is a screening estimate for adults aged 20 and over, not a diagnosis. It cannot tell muscle from fat or water, and it may underestimate health risk for some people. This calculator does not store or send your measurements.

Picture of Dr. Hecham Harb

Dr. Hecham Harb

Consultant Endocrinologist & Medical Director

BMI calculator: what your body mass index means

Book Your Consultation

  • Specialist consultation
  • Personalized Coaching
  • Body Composition Analysis
Book your consultation
Quick answer

BMI, or body mass index, is your weight in kilograms divided by your height in metres squared. The Centers for Disease Control and Prevention (CDC) uses four categories for adults aged 20 and over. A BMI below 18.5 is underweight, 18.5 to under 25 is healthy weight, 25 to under 30 is overweight and 30 or above is obesity. BMI is a screening estimate and does not measure body fat.

Key takeaways
  • In pounds and inches, the CDC gives the formula as weight divided by height in inches squared, multiplied by 703.
  • The CDC divides obesity into class 1 from 30 to under 35, class 2 from 35 to under 40 and class 3, or severe, obesity at 40 or above.
  • The CDC has a separate calculator for children and teenagers aged 2 to 19, so the adult categories do not apply to them.
  • The NHS notes that BMI cannot tell the difference between muscle and fat, so a muscular person may be classed as overweight with little body fat.
  • For many people of South Asian or Arab ancestry, metabolic risk can rise at a lower BMI than the standard adult cut-offs suggest.
  • Weight loss medication is generally considered at a BMI of 30 or above, or 27 or above with a weight-related condition. Eligibility also depends on the approved use of each medication and on a clinical assessment.
  • At Endocare, a body composition analysis is part of every consultation at no extra charge and gives an estimate of fat, muscle and water.
In one line: A BMI result can prompt a health check, but it cannot diagnose a condition on its own.

01  How to use the BMI calculator

In metric units, the calculator takes your height in centimetres and your weight in kilograms. In imperial units, it takes your height in feet and inches and your weight in pounds.

It shows your BMI to one decimal place, with the adult category that the result falls in. The calculator does not store or send your measurements.

BMI is calculated from your height and weight only. In metric units, BMI is your weight in kilograms divided by the square of your height in metres. The CDC formulas give the imperial version: 703 multiplied by your weight in pounds, divided by your height in inches squared.

For example, at a height of 170 cm and a weight of 72 kg, BMI is 72 divided by 2.89, the square of 1.7, which gives 24.9. That result falls in the healthy weight range for adults. In imperial units, at 5 ft 10 in and 200 lb, BMI is 703 multiplied by 200, divided by 4,900, the square of 70 inches, which gives 28.7, in the overweight range.

The CDC adult BMI categories place each adult result in one of the bands below.

BMI category (adults)BMI
UnderweightBelow 18.5
Healthy weight18.5 to under 25
Overweight25 to under 30
Obesity, class 130 to under 35
Obesity, class 235 to under 40
Obesity, class 3 (severe)40 or above
 

The bands have no gaps, so a result of exactly 25.0 is in the overweight band and a result of 24.9 is in the healthy weight band. The World Health Organization uses the same thresholds for adults, defining overweight as a BMI of 25 or above and obesity as a BMI of 30 or above.

The UAE National Health Survey 2017 to 2018, published by the Ministry of Health and Prevention, found obesity in 27.8% of adults aged 18 to 69. Our page on obesity treatment in Dubai explains how obesity is defined and treated.

For adults, no. The CDC states that for adults aged 20 and over, BMI categories are based on BMI regardless of age, sex or race. The calculation is also the same, so a man and a woman of the same height and weight have the same BMI.

Two people with the same BMI can still carry different amounts of fat and muscle. This is one reason a doctor looks at more than one measure when assessing weight.

The CDC notes that BMI does not distinguish between fat, muscle and bone mass, which all influence weight. The NHS adds that someone with a lot of muscle may have a BMI in the overweight or obesity range despite having little body fat.

South Asian and Arab ancestry both carry metabolic risk at a lower body weight than European ancestry does, which is why your endocrinologist reads your weight alongside your body composition analysis. For many patients in the UAE, lower ethnicity-specific waist or BMI thresholds may therefore be more appropriate.

At Endocare, body composition analysis is included free of charge at every consultation. Body composition analysis estimates body fat, muscle mass and body water. Repeated measurements help your endocrinologist understand how your body is changing beyond the number on the scale. Our article on the difference between fat loss and weight loss explains what the analysis adds.

Your BMI is one of the measures a doctor uses when deciding whether treatment may help. Weight loss medication is generally considered for patients with a BMI of 30 or above, or 27 or above when weight-related health conditions are present. Eligibility also depends on the approved use of each medication. Your endocrinologist will assess whether medication is appropriate based on your individual health and weight profile. For many patients with a smaller weight loss goal, the focus is on a personalised nutrition and activity plan with regular follow-up.

Patients should not decide by themselves to start a GLP-1 medication. A doctor’s review is critical to ensure the treatment is safe and appropriate for the individual. Our article on who qualifies for weight loss injections sets out the criteria in more detail, and our guide to GLP-1 medications explains how they work.

A BMI below 18.5 can also be a reason to see a doctor. The NHS advice on unintentional weight loss recommends seeing a GP if you keep losing weight without changing your diet or exercise routine.

No. BMI does not show where fat is stored, including visceral fat around the organs. The NHS guidance on diagnosing obesity advises keeping your waist size to less than half your height. A body composition analysis can estimate visceral fat and provide a visceral fat rating that can be tracked over time.

Not to judge your weight during pregnancy. The NHS lists pregnancy among the situations in which its adult BMI calculator should not be used. Your doctor or midwife can advise you on weight during pregnancy.

No. The adult categories apply from the age of 20. The CDC directs children and teenagers aged 2 to 19 to a separate calculator for children and teens. A paediatrician can explain a child’s result.

Not necessarily. The CDC adult BMI calculator describes BMI as one potential health indicator that should be considered with other factors when assessing an individual’s health. A doctor may also look at your waist size, blood pressure, blood tests and body composition.

A medical assessment is a sensible next step. In the UAE, you can see an endocrinologist directly, with no GP referral needed, for concerns related to hormones, weight, metabolism or blood sugar. If you plan to use health insurance, we recommend checking your policy before you book, because some insurers require a referral or pre-approval. A doctor will look at your BMI together with your medical history, blood pressure and any relevant blood tests. Our guide to finding a weight loss doctor in Dubai explains which doctors treat weight-related conditions.

Check your weight and metabolic health at Endocare

At our Dubai clinic, your endocrinologist will assess you, review your blood tests, carry out a body composition analysis and discuss whether treatment is appropriate for you. You can book a weight loss consultation on +971 4 285 3885 or send us a message on WhatsApp.

Book Your Consultation

  • Specialist consultation
  • Personalized Coaching
  • Body Composition Analysis
Book your consultation