BMI = person’s weight (kg) / (height (m)*height (m))

• Result evaluation:

– Less than 18.5: less than normal weight.

– 18.5 and greater and less than: 25 within normal weight.

– 25 and greater and less than: 30 and greater than and less than normal weight (overweight).

– 30 and greater and less than 35: first degree obesity (moderate).

– 35 and greater and less than 40: second degree obesity (moderate).

– 40 and greater: third degree obesity (excessive).

Reading your weight on the scale is not enough to determine if you have a healthy, ideal weight or not.

For example, a tall and slender person may weigh more than a short and stout person, but both can be healthy as long as their weight is appropriate for their height.

Moreover, the ideal weight differs between men and women of similar heights, and it also changes with age.

So how do you know if you fall within the healthy weight range?

The accurate answer is to use** the BMI calculator** to determine your body mass index and calculate your ideal weight.

In this article, we will learn about:

- What is the BMI calculator and how to use it?
- Factors affecting the calculation of the appropriate body weight.
- How to calculate the ideal weight according to height and age for women, men, and children.
- Learn about other methods for calculating the appropriate body weight.
- How to know if you are obese without a scale, and at what weight does morbid obesity begin?

**What is the BMI Calculator?**

The Body Mass Index (BMI) is an easy and inexpensive medical screening method used to determine a person’s weight category.

The BMI calculator relies solely on a person’s weight and height.

Weight categories are divided into:

- Underweight
- Healthy weight
- Overweight
- Obesity
- Morbid obesity

The BMI calculator works using the following formula:

Weight (kg) ÷ (Height (m) × Height (m))

### How do you use the BMI calculator?

All you need to do is select your gender, then enter your weight in kg and your height in meters, and the BMI calculator will give you your body mass index.

**What are the Factors Affecting the Calculation of Ideal Body Weight?**

There are many factors that influence the calculation of body mass, some of which a person cannot control, such as:

- Gender

- Women are more susceptible to obesity than men.
- Men tend to lose absolute weight more easily than women.

- Age

- As we age, our lifestyle becomes less active, increasing the risk of obesity.
- Muscle mass also decreases with age, often leading to a slower metabolism, which can contribute to weight gain.

- Ethnicity: There are significant differences in the prevalence of obesity among different ethnic groups.

- Nearly 4 out of 5 African American women are overweight or obese.
- African American women are more likely to be obese than non-Hispanic white women.
- Obesity is more prevalent among Hispanic youth than non-Hispanic Asian youth.

- Genetics

- The genes a person inherits from their parents determine their susceptibility to weight gain.
- Individuals with obese parents and grandparents are more likely to become obese than those with parents and grandparents of normal weight.

- Certain Diseases

- Some diseases can lead to obesity, such as hypothyroidism, Cushing’s syndrome.
- Arthritis can lead to decreased activity and, consequently, weight gain.

### Other factors that can be controlled include:

- Physical Activity: The more physically active and engaged in exercise a person is, the more calories they burn, leading to a healthier weight.
- Diet: The quantity and type of food consumed can contribute to obesity or weight loss. Fats require less energy to digest than proteins and carbohydrates.
- Environmental Factors such as viruses, microbes, and chemicals that disrupt endocrine function.
- Geographical areas with limited access to healthy food options.
- Psychological State:
- Sleep: Lack of adequate sleep can lead to hormonal changes that increase appetite. Excessive sleep can also lead to cravings for high-calorie and carbohydrate-rich foods, contributing to weight gain.
- Certain Medications: Some medications can cause weight gain if not balanced with a proper diet and physical activity, such as:
- Certain antidepressants
- Diabetes medications
- Some beta-blockers (high blood pressure medications)

**Calculating Weight and Height for Children**

A child’s BMI is calculated in the same way as an adult’s, but the interpretation of the results is different.

- For adults, BMI classification does not depend on age or gender, unlike children and adolescents aged 2 to 20 years, for whom BMI is interpreted relative to the child’s age and gender.
- The amount of body fat changes with age and differs by gender.
- A child’s BMI is given as a percentile, which indicates how their BMI compares to other children of the same age and gender.

**What are the Other Methods for Calculating the Appropriate Body Weight?**

The BMI calculator is not the only tool for calculating ideal weight; other methods include:

### 1. Monreau-Domeniu Formula:

This formula provides a way to calculate ideal weight by considering height and wrist circumference:

Ideal Weight = (Height – 100 + (4 × Wrist Circumference)) ÷ 2

### 2. Broca’s Formula:

In this formula, only height is considered for calculating ideal weight and obesity:

Ideal Weight = Height – 100

### 3. Creff’s Formula:

This is a modified version of Broca’s formula, taking into account height, age, and a leanness index for calculating ideal weight and obesity.

The formula is expressed as:

Ideal Weight = (Height – 100 + (Age ÷ 10)) × 0.9 × Leanness Index

Leanness Index:

0.9 | Lean |

1 | Normal |

1.1 | Stout |

### 4. Lorentz’s Formula:

In Lorentz’s formula, ideal weight is simply calculated based on height and gender, also being a modified version of Broca’s formula.

Ideal Weight for Men = (Height – 100 – (Height – 150) ÷ 4)

Ideal Weight for Women = (Height – 100 – (Height – 150) ÷ 2)

### 5. Hammond’s Formula:

This formula relies solely on height to calculate ideal weight.

Ideal Weight for Men = 48 kg for the first 150 cm of height + 1.1 kg for every additional cm

Ideal Weight for Women = 48 kg for the first 150 cm of height + 0.9 kg for every additional cm

**At What Weight Does Morbid Obesity Begin?**

Calculating the Body Mass Index (BMI) is the appropriate procedure for screening for obesity and its associated health risks. Based on BMI, obesity can be classified as follows:

Obesity Classification | BMI |

Class 1 | 30 to less than 35 |

Class 2 | 35 to less than 40 |

Class 3 (Morbid Obesity) | 40 and above |

**How to Know If You’re Obese Without a Scale?**

You can determine if you are obese without a scale by measuring your waist-to-height ratio, which can tell you if you have excess abdominal fat.

Measure your waist circumference and divide it by your height. If the ratio is 0.5 or higher, it indicates that you may be at an increased risk of health problems.

**For example**, if a person’s height is 170 cm and their waist measurement is 68 cm, dividing 68 by 170 gives a result of 0.4, which is less than 0.5, meaning this person is of normal weight.

Another person with a height of 160 cm and a waist measurement of 90 cm would have a waist-to-height ratio of 0.56 (90 ÷ 160), which is higher than 0.5, indicating that this person may have excess abdominal fat.