BMI Calculator for Adult Men, Women and Children

What is BMI ? BMI Calculator ( Body Mass Index) is a formula that’s used to find out if you’re a healthy weight for your height.

The Centers for Disease Control and Prevention (CDC) defines BMI as “a person’s weight in kilograms divided by the square of their height in meters”.

Metric (Kilograms)
Imperial (Stone & Pounds)


Metric (Centimetres)
Imperial (Feet & Inches)



BMI Result


What’s a Healthy BMI?

BMI calculator chart
BMIWeight Status
Below 18.5 Underweight
18.5 – 24.9Normal or Healthy Weight
25.0 – 29.9Overweight
30.0 and AboveObese
BMI Weight Status Categories

A BMI between 18.5 and 24.9 is considered healthy.

What should your BMI Be for Your Age and Weight?

The BMI calculator only takes into account your weight and height when calculating your BMI. Also, a number of different factors determine what our healthy weight should be. These factors include; , muscle-fat ratio, height, body fat position, sex, and age.

BMI Calculator for Women

BMI calculation for Women

You might be wondering! What is the best BMI for a woman? Well, Health practitioners consider a healthy BMI for women to be between 18.5–24.9, and a BMI of 30 or above may indicate obesity.

Measuring your BMI can help you understand whether you are underweight, have a healthy weight, overweight or obese.

BMI calculation do have some drawbacks for women; it does not distinguish between the weight that comes from fat, muscle, and bone.

This is very significant because the proportion of muscle, fat, and bone in the body typically changes as people age, especially among females.

Therefore because we lose body mass while we age and gain belly fat it means a 60-year old that weighs about the same as she did 30 years ago will have a BMI that falls in the healthy range despite having more body fat due to age.

Given the above reasons, using BMI alone may be quite inaccurate when trying to evaluate a woman’s overall health. This is especially significant for women who might be above 60 years, very muscular, or women who have abdominal fat but are otherwise an average weight and healthy.

BMI Calculator Men

BMI Calculation for Men

The BMI measurement used for women is the same used for men. The BMI calculator and chart may not be suitable for very muscular men, e.g. Wrestlers. This is because having a lot of muscle which is denser than fat may put you in the overweight category, even if you have very little body fat.

BMI Calculator for Kids

For children between 2 and 18 years, the BMI calculator uses a different set of data. It takes into account the child’s age, gender, height and weight.

Children who are overweight are considered to be at risk of a variety of health conditions. And they may also end up being overweight as adults.

Children between 2 and 18 have their BMI worked out in percentiles.

 Percentiles is a measurement that express a child’s BMI in centile to show how their BMI compares with those who took part in a national survey.

For example; A boy on the 65th centile is heavier than 65 out of 100 other boys his age.

BMI Chart Range for Children

UnderweightYour child is underweight if they are on the 2nd centile and below.
Healthy WeightYour child has a healthy weight if they are between the 2nd and 91st centile.
OverweightYour child is very overweight if they are between the 91st and 98th centile.
ObeseYour child is obese if they are on the 98th centile and above.

Using an Adult BMI Calculator for Children

It is not advisable to use an adult BMI calculator for children as it only provides the BMI value and not the BMI percentile which makes it inappropriate.

However, if your child under 18 has a BMI of 30kg/m2 or higher, they are most likely obese.

If you are worried or concerned about your child’s weight, please see a doctor as they can easily advise you of some lifestyle changes that’ll benefit your child.

BMI for Asians

Researchers have found that at the same BMI, Asians have more than double the risk of developing type 2 diabetes,  hypertension, and cardiovascular disease than their white European counterparts, and a higher risk of dying early from cardiovascular disease or any cause.

There’s also currently a debate about whether the cut points for overweight and obesity should be lower for Asians than for other ethnic groups because when compared to white Europeans of the same BMI, Asians have 3 to 5 percent higher total body fat.

South Asians, in particular, do possess very high levels of body fat and are more susceptible to developing abdominal obesity, which may account for their very high risk of type 2 diabetes and cardiovascular disease.  An Adult Asian with a BMI of 23 or more is at increased risk of developing weight-related diseases.

Is BMI a Good Health Indicator?

Even though BMI is very useful for keeping track of our health. There are some situations and group of people that is it not suitable for and they include:

  • Some ethnic groups e.g. Asians.
  • Athletes with a lot of muscles.
  • Children and Teenagers.
  • Pregnant women. BMI calculation is usually based on your weight before your pregnancy, your BMI will go up when you’re pregnant.
  • Those less than 1.5m/ 5ft tall.
  • Older people, those above 65 years.

Alternative Ways to Measure BMI

Fortunately, there are other ways to measure your overall health especially if you feel Body Mass Index(BMI) is not a reliable option for you. This might be because you are very muscular or because you are above 60.

These methods include measuring your waist circumference, your waist to height and waist to hip ratio.

Waist Circumference

Measuring your waist circumference is a great way to check you don’t have too much fat building up around your stomach.

How To Measure Your Waist Circumference

  • Find the bottom of your ribs and the top of your hips with the tape parallel to the floor.
  • Wrap a tape measure around your waist midway between these points.
  • It’s very important that you are breathing out when you measure.

Notwithstanding what your height or weight is, you should make an effort to lose some belly fat/ weight if your waist circumference is;

  • 94cm (37ins) or more for men
  • 80cm (31.5ins) or more for women

Waist to Height Ratio

A recent study carried out has proven that waist to height ratio is the best method of measurement for predicting your whole body fat level

To measure your weight to height ratio

  • you need to measure your waist circumference and your height, you can use either the imperial (inches) or metric (cm) measurements,
  • then simply divide your waist circumference by your height.

If the value is 0.5 or it indicates that you have a healthy weight. If it’s above 0.59, it means you are overweight.

Waist to Hip Ratio

Waist to hip ratio is used to compare the size of your waist with that of your hips.

To measure your waist to hip ratio

  • You’ll need to measure around the narrowest part of your waist which is usually just above the belly button.
  • Take your hip measurement by measuring the widest part.
  • Divide your waist measurement by your hip measurement.

You should make effort to improve your lifestyle and reduce your abdominal weight if your waist to hip ratio is;

  •  Greater than 0.85 for women.
  • Greater than 1.00 for men.

What to do If I’m worried about my BMI results?

BMI health chart

If the BMI calculator finds that your BMI is outside of the healthy range, I would strongly advise you to talk to your doctor before making any really big changes to your diet or the amount of physical activity you do to reduce your weight.

However, waiting to speak to a professional shouldn’t stop you from making small changes today. If the BMI calculator finds you are more than the ideal weight, losing just a few pounds is a great start to improving your overall health.

Simple regular exercises such as walking, going up and down the stairs, and also cutting down your food intake can help you lose weight, improve your health and also help to lower your risk of cancer and other diseases linked to being overweight.

If your BMI indicates you are less than the ideal weight, gaining some weight by eating the right type of healthy food could benefit your overall health.

Sharing is caring 😊

Leave a Reply

Your email address will not be published. Required fields are marked *