Healthy Weight Calculator

Weight is an important determinant of health, which is why “how much should I weigh” is a common question among young people and adults. 



Several factors ranging from age, gender, body mass index, BMI and body frame size (involve height, weight, waist hip ratio, etc.), body fat percentage and distribution, muscle mass, etc., factor in when determining your ideal body weight.

While getting exact idea of a healthy body weight might be a complex medical process, an online healthy weight calculator can be used for a rough estimate.

In this post, we explain ideal weight calculators and how they can help you achieve a normal weight (that falls in the healthy BMI range), and good health.

What Is An Ideal Weight Calculator?

In simple terms, healthy weight is defined as a measurement that is associated with the lowest incidence /risk of developing metabolic disorders, heart diseases, other health problems, and hence, the lowest mortality (for a given height, age, and sex).

An ideal body weight calculator is a useful tool that essentially uses formulas involving height, age, and gender to a normal, healthy weight measure for you.

Popular Formulas Used For Ideal Body Weight (IBW)

Here are the popular formulas various online body weight calculators use to give you a rough idea of your ideal healthy weight:

Robinson’s Equation

52 kg + [1.9 kg (for men) or 1.7 kg (for women)] per every inch over 5 feet

Here’s an example to explain how you can calculate normal weight using Robinson’s formula.

Consider a man measuring 5’5″.

To calculate his ideal weight, we multiply 1.9 (which is the standard constant when using Robinson’s formula for men) by 5 (because the person is 5 inches over 5 feet). The result is added to 52.

52 + (1.9 x 5) = 61.5 kg

According to Robinson’s equation, 61.5 kg is the healthy weight for a 5’5″ man.

Miller’s Equation

56.2 kg + [1.41 kg (for men) or 1.36 kg (for women)] per every inch over 5 feet

Devine’s Equation

Height (cm) – [105 (for men) or 108 (for women)]

Hamwi’s Equation

48 kg for the first 5 ft. + 2.7  kg for each additional inch

45.3 kg for the first 5 ft. + 2.2 kg for each additional inch

Factors Influencing Ideal Body Weight

Weight varies with body frame size, which is why there’s no one ideal body weight for all.

Here are the major factors that influence your ideal body weight measure:


Age is an important factor when it comes to healthy body weight.

Girls and boys reach their final adult height a little after puberty (14 to 15 years of age for girls and 16 to 17 for boys. Therefore, theoretically, age should not hold significant importance when it comes to IBW.

However, height and body composition gradually change as you age. According to research, people typically lose almost one centimeter every ten years after 40 because of changes in bones, joints, and muscles.

Since signs of aging naturally become more prominent with increasing age, the reduction in height becomes more rapid as you approach your 70s.

Additionally, aging reduces lean mass and bone density while the body fat percentage increases. The distribution of fat mass dominates the abdominal region, which is associated with an increased risk of cardiovascular disorders and diabetes.

Due to this, age is considered in healthy weight calculation.

Gender, Muscle Mass, And Body Fat

All formulas used to calculate healthy, normal weight have adjustments specific for both sexes.

This is because fat and muscle percentage varies for both genders. Women have more fat mass than men. To add to this, the deposition of adipose (fat tissue) also differs. While women tend to accumulate body fat around the hips and thighs, men are more likely to have it around the trunk and abdomen.

In contrast to body fat percentage and its distribution, men have more muscles than women.

Due to the extra muscles (and thus, need more energy), men physiologically burn calories (derived from macronutrients) faster as compared to women. On the other hand, women have better metabolism of micronutrients (vitamins, minerals, etc.)

Fats can be stored as an energy reserve and broken down into ketone bodies to provide energy in a state of starvation /fasting. Since men have less fat and utilize energy at a faster rate, eating more calories is important to them so as to maintain an adequate energy level.

To add to this, different health risks are associated with high /low body fat and muscle mass, which is why ideal /normal calorie distribution also varies for the two sexes.


All the formulas created for ideal body weight assume that weight is directly proportional and linear in relation to height.

Therefore, height is included in healthy weight calculations.

Waist Size (Circumference)

One of the loopholes of IBW calculators is that they do not measure waist size when calculating weight.

Several pieces of research point to the fact that weight around the midsection poses a higher risk of metabolic diseases.

Increased waist circumference points to excess fat, which implies an increased incidence of heart diseases, hypertension, high cholesterol (in the blood), and diabetes. Additionally, fluctuations in body weight have a significant correlation with alteration in waist size.

Waist size is often considered a better alternative to BMI for a more accurate idea of your health.

Waist Size And Risk Of Metabolic Diseases In Men

Here is the classification of waist size in men, and the corresponding risk of developing health problems:

  • < 94 cm or 37 in = low risk
  • 94 cm to 102 cm or 37 to 40 in = high risk
  • > 102 cm or 40 in = very high risk

Waist Size And Risk Of Metabolic Diseases In Women

Here’s the waist size classification for women, and their relative incidence of metabolic problems:

  • < 80 cm or 31.5 in = low risk
  • 80 cm to 88 cm or 31.5 into 34.6 in = high risk
  • > 88cm = very high risk

The varying body fat distribution and body composition explain the difference in the classification of waist size for men and women.

Body Frame Size

Body frame size is the calculation of a person’s wrist circumference in relation to their height. It determines bone size and density and plays a huge role in the determination of ideal body weight.

Frame Size Classification For Women

Here is the frame size classification for women of different heights:

Height < 5’2”

  • Small = wrist size < 5.5 in
  • Medium = wrist size 5.5 into 5.75 in
  • Large = wrist size over 5.75 in

Height 5’2” to 5’5”

  • Small = wrist size < 6 in
  • Medium = wrist size six into 6.25 in
  • Large = wrist size over 6.25 in

Height > 5’5”

  • Small = wrist size < 6.25 in
  • Medium = wrist size 6.25 into 6.5 in
  • Large = wrist size > 6.5 in

Frame Size For Men

In men, frame size classification is independent of height.

  • Small boned = wrist size 5.5 into 6.5 in
  • Medium boned = wrist size 6.5 into 7.5 in
  • Large boned = wrist size >7.5 in
  • Anyone having a large frame will have higher healthy weight, and thus a different BMI result than someone with a small frame.

Activity Level

IBW is also defined by a person’s nature of work and activity level.

For example, naturally, it is expected of athletes to have more muscle mass, which increases their weight. The ‘normal’ weight also varies for different sports.

In terms of activity level, anyone who is more physically active or engages in strenuous exercises burns more calories and, therefore, has a higher daily calorie requirement than an average individual.

What Is Body Mass Index or BMI?

When discussing ideal body weight, it is crucial to understand body mass index BMI.

BMI is a scale used to gauge general health, especially in terms of weight. Essentially, it is a ratio of weight (in kg) and height (in m2).

Introduced in the 19th century by Lambert Adolphe Jacques Quetelet, the BMI chart classifies adult body weight into four types; underweight, healthy, overweight, and obese.

The body weight to height ratio falls in one of four categories, which indicates your health.

According to the World Health Organization, here’s the BMI classification for adults:

  • underweight = <18.5
  • healthy = 18.5 to <25
  • overweight = 25 to <30
  • Obese = 30 or higher

Note that this chart applies to people above 20.

For children and young adults (2 to 20 years of age), BMI growth charts or graphs have been designed. When the height and weight are plotted on the graph, they correspond with a percentile (calibrated on the graph).

Here are the different BMI percentiles and their respective weight category:

  • <5% = underweight
  • 5% to 85% = healthy
  • 85% to 95% = overweight
  • >95% = obese

You can easily check your BMI using a free body mass index or BMI calculator available online.

Is BMI And Ideal Body Weight The Same?

Understanding BMI raises a very important question; are BMI and healthy /ideal body weight the same?

While the two are often confused, they are not the same. BMI is one of the several ways IBW can be calculated. It is also the most used method, as body weight and height are easy to calculate.

BMI is often believed to be the most accurate indicator of health, and while it is helpful, BMI readings can be misleading due to certain limitations of the formula.

Here are some of the major factors affecting weight (and hence the IBW) that BMI charts don’t consider:

  • Race
  • Water weight
  • Muscle mass
  • Bone density
  • Fat distribution

For better idea of IBW, alternatives to BMI, like measuring waist, weight scales, and DEXA (the gold standard for measurement of body composition), are used.

Health Effects Of Obesity

Most people use ideal body weight calculator to lose weight and fall into a healthy BMI range. Therefore, when speaking of normal weight, it is crucial to discuss obesity and its associated health conditions.

The major ones are:

  • Hypertension (high blood pressure)
  • Hypercholesterolemia (high cholesterol)
  • Risk of metabolic syndrome
  • Higher risk of heart disease and atherosclerosis (constriction /obstruction in coronary arteries due to fat deposits)
  • Type 2 diabetes (insulin resistance leads to development of diabetes i.e. high blood sugar)
  • Stroke (interruption or severance of blood supply to the brain)
  • Gallbladder disease (increased risk of gall stones)
  • Sleep apnea (fat deposits in the upper airway tract narrow the airway, interfering with breathing, thus resulting in hypoxic episodes during sleep)
  • Impairment of functions of vital organs like the liver and kidneys (due to excess cholesterol)
  • Cancer of GIT and reproductive organs (due to long-lasting inflammation and higher levels of insulin, and growth factors)

Obesity is one of the risk factors of bile acid malabsorption as well.

The Right Way To Lose Weight

Obesity stands as an epidemic for US adults and the fifth leading risk of global mortalities.

However, if you’re overweight, starving yourself is not the way to go.

There are healthy ways to lose excess weight without depriving yourself of adequate energy levels and nutrients essential to survive.

When it comes to weight, you need to consider the three main macronutrients that constitute most of it. These are proteins, fats, and carbohydrates.

They are important for chemical reactions, enzyme and hormone synthesis, and several other vital functions in the body. Therefore, your diet should contain all three macronutrients.

Remember that one gram of protein, carbohydrate, and fat metabolizes into 4, 4, and 9 calories, respectively. The daily requirement of each of these three varies per gender, age, current weight, and height.

It is also essential to consider good and bad (healthy and unhealthy) calories, as processed foods and other artificial sources of macros can have adverse effects like unhealthy weight gain /loss, metabolic disorders, etc.

A good quality online macro calculator can help you come up with a meal plan that’s healthy, nutritious, and in line with your weight goals.

Apart from ensuring a nutritious and healthy meal, it is also critical to engage in regular exercise and other physical activities. This is because burning more calories than you consume is literally the key if you want to lose weight.

Quitting cigarettes, reducing your alcohol intake, and ensuring minimal stress also go a long way in controlling weight and lowering the risk of diseases.

Healthy Ways To Gain Weight

If you are categorized as underweight on the body mass index calculator, you might be interested in putting on weight.

Here are some tips for adults who want to gain weight:

  • Choose a high protein diet like yoghurt, butter, fish, nuts, seeds, and egg, as it boosts your calorie intake and muscle mass, leading to a healthy weight gain.
  • Consider taking protein supplements, bars, shakes, etc. However, make sure to get expert consultation to ensure it does not cause health complications.
  • Eat snacks that are high in calories.
  • Exercise for an ideal body shape, and an increased muscle mass.
  • Avoid smoking and drinking as it can cause unhealthy weight gain.
  • Avoid eating fatty food, as it can end in fat deposition, which is harmful, and causes several diseases.

It is critical to remember that significant or sudden increase or reduction in weight can be an indicator of underlying disease. Therefore, while working towards your IBW, it is also essential to check with a doctor.

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