BMI Calculator lbs

The Body Mass Index (BMI) Calculator can be used to determine your BMI value and weight status while taking your age into account. For the International System of Units, use the “Metric Units” page, or the “Other Units” option to convert units into either US or metric units. The Ponderal Index, in addition to BMI, is calculated by the calculator, and both are explored in depth below.


Introduction to BMI

BMI is a scale that measures a person’s leanness or corpulence based on their height and weight. It is used to estimate tissue mass. It is commonly used as a general indicator of whether a person’s body weight is appropriate for their height. Specifically, the BMI value is used to determine whether a person is underweight, normal weight, overweight, or obese, based on where the value falls within the range. These BMI levels vary by geography and age and are frequently further subdivided into subcategories like severely underweight or very severely obese. Being overweight or underweight can have serious health consequences, therefore while BMI is an inaccurate predictor of healthy body weight, it can help determine whether further testing or action is necessary. The multiple groups depending on BMI that the calculator uses are listed in the table below.

Table of BMI for Adults

Based on BMI readings, this is the World Health Organization’s (WHO) recommended adult body weight. It is appropriate for both men and women over the age of 18.

CategoryBMI range – kg/m2
Severe Thinness< 16
Moderate Thinness16 – 17
Mild Thinness17 – 18.5
Normal18.5 – 25
Overweight25 – 30
Obese Class I30 – 35
Obese Class II35 – 40
Obese Class III> 40

BMI chart for adults

Based on statistics from the World Health Organization, this graph depicts BMI categories. Within a major classification, the dashed lines denote subdivisions.

BMI chart for Adults

BMI table for children and teens, age 2-20

For children and teenagers aged 2 to 20, the Centers for Disease Control and Prevention (CDC) recommends BMI categorization.

CategoryPercentile Range
Healthy weight5% – 85%
At the risk of overweight85% – 95%

Risks associated with being overweight

Overweight people are more likely to develop a variety of significant diseases and health problems. According to the Centers for Disease Control and Prevention (CDC), the following are some of the risks:

  • Blood pressure problems
  • Higher levels of LDL cholesterol, sometimes known as “bad cholesterol,” lower levels of HDL cholesterol, which is healthy cholesterol in moderation, and high triglyceride levels
  • Diabetes type 2
  • Coronary artery disease (CAD)
  • Stroke
  • Gallbladder problems
  • Osteoarthritis is a form of the joint disease characterized by cartilage breakdown.
  • Breathing issues and sleep apnea
  • Several cancers (endometrial, breast, colon, kidney, gallbladder, liver)
  • Life of poor quality.
  • Clinical depression, anxiety, and other mental diseases
  • Body aches and difficulties performing specific bodily tasks
  • When compared to people with a healthy BMI, there is a higher chance of death.

As can be seen from the list above, being overweight can have a variety of unpleasant, and in some cases fatal, consequences. In general, a person should attempt to keep their BMI below 25 kg/m2, but they should first visit their doctor to see whether they need to make any lifestyle adjustments to get healthy.

Underweight carries a number of risks.

  • Being underweight comes with its own set of dangers, which are described below:
  • Anemia, malnutrition, and vitamin deficiencies (lowered ability to carry blood vessels)
  • Osteoporosis is a bone-thinning disease that increases the chance of fracturing a bone.
  • Immune system dysfunction
  • Problems with growth and development, especially in children and teenagers
  • Hormonal abnormalities that alter the menstrual cycle may cause reproductive difficulties in women. Women who are underweight have an increased risk of miscarriage in the first trimester.
  • Surgery-related problems that could occur
  • When compared to people with a healthy BMI, there is a higher chance of death.

Being underweight can sometimes indicate an underlying ailment or disease, such as anorexia nervosa, which carries its own set of hazards. If you or someone you know appears to be underweight, consult your doctor, especially if the cause does not appear to be clear.

BMI’s Limitations

BMI is a commonly used and valuable predictor of healthy body weight, however, it has limitations. BMI is merely an estimate that does not take into consideration body composition. Because of the broad range of body types and the distribution of muscle, bone mass, and fat, BMI should be used in conjunction with other metrics rather than as the single indicator of a person’s healthy body weight.

In adults:

Because BMI is a measure of extra body weight rather than excess body fat, it cannot be completely accurate. Age, sex, ethnicity, muscle mass, body fat, and exercise level, among other things, all have an impact on BMI. An elderly person who is a healthy weight but is utterly sedentary in their everyday life, for example, may have considerable quantities of excess body fat despite not being overweight. This is unhealthy, but a younger person with a better muscle composition and the same BMI is deemed healthy. It is certainly feasible that athletes, particularly bodybuilders, who are considered overweight because muscle weighs more than fat, are actually at a healthy weight for their body composition. According to the CDC, in general:

  • With the same BMI, older persons have more body fat than younger adults.
  • For an equivalent BMI, women have more body fat than males.
  • Due to their substantial muscle mass, muscular people and highly trained athletes may have higher BMIs.

In children and adolescents:

The same factors that restrict BMI’s effectiveness in adults can also limit its effectiveness in children and adolescents. Height and sexual maturation can also influence BMI and body fat levels in children. Obese children’s BMI is a better measure of excess body fat than overweight children’s BMI, which could be the consequence of increased fat or fat-free mass (all body components except for fat, which includes water, organs, muscle, etc.). The variation in BMI in skinny children can also be related to fat-free mass.

However, for 90-95 percent of the population, BMI is a good predictor of body fat, and it can be used in conjunction with other factors to assist establish an individual’s healthy weight.

BMI formula

Using a 5’10” 160-pound individual as an example, the formulae for determining BMI in the International System of Units (SI) and the US customary system (USC) are as follows:

BMI formula: weight (in kilograms) divided by height squared (in meters), expressed as kg/m2.

  • Formula: Weight (kg)/[height (m)]2
  • Example: weight = 60 kg and height = 1.50 m
  • Calculation: 60/ (1.50)2= 60/2.25=26.67

In the English System, it is calculated as follows: your weight (in pounds) divided by height squared (in inches) multiplied by 703.

  • Formula: [Weight (lb)/height (in)]2 x 703
  • Example: weight = 180 lb and height = 68 in
  • Calculation: [180/ (68)2] x 703= [180/4624] x 703= 27.37

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