BMI Calculator - Understand Your Body Better

What Is Body Mass Index (BMI)?

Body Mass Index (BMI) is a simple way to assess whether your weight is appropriate for your height. It's calculated using your height and weight and helps classify your weight status - from underweight to obese - based on standard health guidelines.
Although BMI doesn't directly measure body fat, it's a useful tool for identifying potential health risks related to weight.

Introduction to the body mass index (BMI)

The WHO (World Health Organization) has developed different BMI (Body Mass Index) classification standards based on different age groups and genders. The following are the common BMI classification standards of WHO (the details of the classification vary according to age and gender)

• BMI categories for adults (18 years and older)

  For adults, the BMI classification standards are unified and do not distinguish between genders, but there can usually be some variations based on age, body fat distribution, etc.

  BMI	Classification	Potential Health Risk
  < 18.5	Underweight	Nutrient deficiency, low immunity, fatigue
  18.5 - 24.9	Normal weight	Low health risk, balanced body composition
  25 - 29.9	Overweight	Increased risk of cardiovascular disease, diabetes
  30 - 34.9	Obesity (Class 1)	High risk of cardiovascular disease, diabetes, hypertension
  35 - 39.9	Obesity (Class 2)	Very high risk of cardiovascular disease, diabetes, hypertension
  > 40	Obesity (Class 3)	Extremely high risk of cardiovascular disease, diabetes, hypertension

• BMI categories for children and adolescents (2-19 years)

  For BMI classification of children and adolescents, WHO uses percentile standards based on age and gender. The healthy range of BMI varies according to different age groups. The standards include the following ranges:

  Percentile	Classification	Potential Health Risk
  < 5th	Underweight	Nutrient deficiency, low immunity, fatigue
  5th - 85th	Normal weight	Low health risk, balanced body composition
  85th - 95th	Overweight	Increased risk of cardiovascular disease, diabetes
  > 95th	Obesity	High risk of cardiovascular disease, diabetes, hypertension

• Gender differences

  Although the WHO BMI standard does not specifically distinguish between adult genders, the relationship between body fat distribution and BMI may be different for men and women in some special health assessments. Generally speaking, women have higher body fat content than men, which may also affect the assessment of underweight, normal weight, overweight or obesity. However, the WHO standard is generally a unified classification standard applicable to all genders.

How to calculate BMI

If you want to calculate your BMI, you have to find out your weight and height first. Once you know these values, you can arrive at the result by following the two steps mentioned below:

• Multiply your height by itself (height X height). For example, if you are 1.75 meters tall, you would multiply 1.75 by 1.75 to get 3.0625.
• Divide your weight by the answer you get in the first step.

Why Is BMI Important?

Your BMI gives you a general idea of whether you are underweight, within a healthy weight range, overweight, or obese. Although BMI does not directly measure body fat, it's a useful starting point for understanding your health.

What your BMI result means

A BMI range of 18.5 to 24.9 is considered a 'healthy weight.' Maintaining a healthy weight may lower your chances of experiencing health issues later on, such as obesity and type 2 diabetes. Aim for a nutritious diet with reduced fat and sugar content, incorporating ample fruits and vegetables. Additionally, strive for regular physical activity, ideally about 30 minutes daily for five days a week.

How to maintain good physical condition

Limitations of BMI

Although BMI is often a practical indicator of healthy weight, it is not suited for every person. Specific groups should carefully consider their BMI outcomes, and in certain cases, the measurement may not be beneficial to use.

• Gender

  The development and body fat composition of girls and boys vary with age. Consequently, a child's age and gender are considered when evaluating their BMI.

• Age

  In aging individuals, increased body fat and muscle loss may cause BMI to underestimate body fat content.

• Muscle

  BMI may misclassify muscular individuals as overweight or obese, as it doesn't differentiate muscle from fat.

• Pregnancy

  Expectant mothers experience weight gain due to their growing baby. Maintaining a healthy pre-pregnancy BMI is advisable to minimise health risks for both mother and child.

• Race

  Certain health concerns may affect individuals of some Black and Asian origins at lower BMIs than others. To learn more, it is advised to discuss this with your GP or practice nurse.

Tips for Maintaining a Healthy Weight

• Eat a balanced diet: Focus on whole foods, lean proteins, fruits, and vegetables. Limit processed sugar and saturated fats.
• Stay active: Aim for at least 150 minutes of moderate-intensity exercise each week (e.g., brisk walking, cycling, swimming).
• Hydrate well: Drink enough water throughout the day.
• Sleep enough: Get 7-9 hours of quality sleep nightly.
• Manage stress: Chronic stress can affect metabolism and appetite.
• Track progress: Periodically check your BMI, but focus on overall wellness, not just the number.

Frequently Asked Questions

• Is BMI always accurate?

  Not entirely. BMI is a general guideline. For muscular individuals, BMI may overestimate body fat, while in others, it may underestimate it.

• What if my BMI is “normal” but I have belly fat?

  You may still have visceral fat, which poses health risks. BMI doesn't reflect fat distribution - waist measurements are also important.

• Can children or elderly people use the same BMI chart?

  No. BMI charts for children and seniors differ, as body composition and fat distribution change with age.

• Can I use BMI during pregnancy?

  BMI is not recommended during pregnancy. Consult your healthcare provider for appropriate weight guidance.

Health Disclaimer

This calculator and table are for educational purposes only. They do not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional for personalized guidance.