Body Mass Index (BMI) Calculator

The online BMI calculator will help you determine your body mass index and understand whether your weight is normal

18.5-24.9
Normal range
99%
Calculation accuracy
Бесплатно
For free

Calculation parameters

About the BMI calculator

Body mass index (BMI) is an indicator that helps assess the proportions of a person's weight to their height. Our online BMI calculator allows you to quickly and accurately determine your body mass index and understand whether your weight is within the normal range.

The BMI calculator is suitable for people of any age and gender. It helps assess weight for height and identify possible health risks associated with being overweight or underweight.

Examples of BMI calculation

Let's look at practical examples of calculating body mass index for different cases:

Example 1: Normal weight

Male, height 175 cm, weight 70 kg

IMT = 70 / (1.75)² = 70 / 3.0625 = 22.86

BMI = 22.86 (normal weight)

Category: Normal (18.5-24.9)

Example 2: Underweight

Woman, height 165 cm, weight 48 kg

IMT = 48 / (1.65)² = 48 / 2.7225 = 17.63

BMI = 17.63 (underweight)

Category: Underweight (<18.5)

Example 3: Overweight

Male, height 180 cm, weight 90 kg

IMT = 90 / (1.80)² = 90 / 3.24 = 27.78

BMI = 27.78 (overweight)

Category: Overweight (25-29.9)

Example 4: Obesity I degree

Woman, height 160 cm, weight 85 kg

IMT = 85 / (1.60)² = 85 / 2.56 = 33.20

IMT = 33.20 (obesity I degrees)

Category: Obesity I degree (30-34.9)

Example 5: Obesity II degree

Male, height 170 cm, weight 110 kg

IMT = 110 / (1.70)² = 110 / 2.89 = 38.06

IMT = 38.06 (2 degree obesity)

Category: Obesity II degree (35-39.9)

Example 6: Obesity III degree

Woman, height 155 cm, weight 95 kg

IMT = 95 / (1.55)² = 95 / 2.4025 = 39.54

BMI = 39.54 (III degree obesity)

Category: Obesity III degree (≥40)

How is BMI calculated?

BMI is calculated using a simple formula that takes into account your height and weight:

ИМТ = Вес (кг) / Рост² (м²)
  • Measure your height in centimeters
  • Weigh yourself and record your weight in kilograms
  • Enter data into the calculator
  • Get result with weight category

Categories of IMT

The World Health Organization (WHO) has defined the following BMI categories:

Lack of mass
ИМТ < 18.5
Consultation with a doctor is recommended
Norm
ИМТ 18.5-24.9
Optimal weight for health
Overweight
ИМТ 25-29.9
Weight loss recommended
Obesity
ИМТ ≥ 30
Medical supervision required

Impact of BMI on health

BMI is an important indicator for assessing health risks:

  • A normal BMI (18.5-24.9) is associated with the lowest health risks
  • Being overweight increases your risk of heart disease
  • Obesity increases the risk of diabetes, hypertension and other diseases
  • Being underweight can also negatively impact your health

BMI restrictions

It is important to understand the limitations of BMI as an indicator:

  • BMI does not take into account muscle mass and body composition
  • In athletes, BMI may be overestimated due to developed muscles
  • In older people, BMI may be less accurate
  • BMI does not take into account the distribution of fat in the body

Online calculator BMI

Our free online BMI calculator will help you quickly determine your body mass index. Just enter your height and weight and get accurate results with health recommendations.

Часто задаваемые вопросы об индексе массы тела

What is body mass index (BMI) and how to calculate it?

Body mass index (BMI or BMI) is an indicator that is calculated by the formula: weight in kilograms divided by the square of height in meters. Formula: BMI = weight (kg) / height² (m²). For example, with a weight of 70 kg and a height of 175 cm: BMI = 70 / (1.75)² = 22.9.

What is the normal body mass index for women?

The normal body mass index for women is 18.5-24.9 kg/m². This is the range that corresponds to the lowest health risks. Values ​​below 18.5 indicate underweight, and values ​​above 25 indicate overweight.

What is the normal body mass index for men?

The normal body mass index for men is also 18.5-24.9 kg/m². This range is optimal for health regardless of gender. A BMI above 25 indicates overweight, and above 30 indicates obesity.

How to calculate BMI online using a calculator?

To calculate your BMI online, enter your height in centimeters and weight in kilograms into the BMI calculator. The system will automatically calculate your body mass index using the formula and show your weight category: normal, underweight, overweight or obese.

What does underweight mean by body mass index?

Underweight is defined as a BMI below 18.5 kg/m². This may indicate malnutrition, health problems or constitutional issues. It is recommended to consult a doctor to assess your health status.

What does overweight mean by body mass index?

Overweight is defined as a BMI of 25-29.9 kg/m². This indicates being above the normal weight range and may increase the risk of cardiovascular disease. It is recommended to review your diet and increase physical activity.

What body mass index is considered obese?

Obesity is diagnosed with a BMI of 30 kg/m² or higher. There are three degrees of obesity: I degree (30-34.9), II degree (35-39.9) and III degree (≥40). Each degree requires medical supervision and supervision.

How to determine ideal weight using body mass index?

The ideal weight for a normal BMI is calculated using the formula: weight = BMI × height². For a normal range of 18.5-24.9, with a height of 170 cm, the ideal weight is from 53.5 to 72 kg. For example, for a BMI of 22: weight = 22 × (1.70)² = 63.6 kg.

Does age affect body mass index?

Although BMI does not directly take into account age, normal values ​​may vary among different age groups. For children and adolescents, special percentile charts are used, but for older adults, the acceptable range may be slightly higher.

Can body mass index be used for athletes?

For athletes, BMI can be an inaccurate indicator because it does not take muscle mass into account. In professional athletes with developed muscles, BMI may be overestimated, although the percentage of body fat is low. In such cases, it is better to use other methods for assessing body composition.

How to calculate normal weight range based on BMI?

The normal weight range is calculated for a BMI of 18.5-24.9. Minimum normal weight = 18.5 × height², maximum = 24.9 × height². For example, with a height of 175 cm: minimum = 18.5 × (1.75)² = 56.7 kg, maximum = 24.9 × (1.75)² = 76.3 kg.

What is BMI and how is it different from BMI?

BMI (Body Mass Index) and BMI (Body Mass Index) are the same thing. BMI is an English abbreviation, and BMI is Russian. Both denote an indicator calculated by dividing weight by the square of height.

What health risks are associated with a high body mass index?

A high BMI (≥25) increases the risk of heart disease, type 2 diabetes, hypertension, joint disease, some cancers, and breathing problems. With a BMI ≥30, the risks increase significantly and require medical intervention.

What are the health risks of having a low body mass index?

A low BMI (<18.5) may indicate malnutrition, weakened immunity, osteoporosis, fertility problems, increased risk of infections and slower recovery from illness. Consultation with a physician is recommended.

How often should you check your body mass index?

It is recommended to check your BMI regularly, for example, once a month when actively working on weight, or once a quarter for general control. To track your weight changes, use our online BMI calculator.

Is it possible to calculate the body mass index for a child?

A standard BMI calculator is not suitable for children, as normal values ​​change with age. For children, special percentile growth charts are used taking into account gender and age. Contact your pediatrician for an assessment of your child's weight.

How to calculate body mass index during pregnancy?

During pregnancy, BMI may not be accurate due to changes in the body. Pre-pregnancy body mass index and pregnancy weight gain are usually assessed. The rate of weight gain depends on the initial BMI: with a normal BMI - 11.5-16 kg.

What are the limits of body mass index?

BMI does not take into account muscle mass, body fat distribution, age, gender and constitution. In athletes, older adults, and pregnant women, the reading may be less accurate. For a more accurate estimate, use additional methods.

How to interpret body mass index results?

BMI <18.5 – underweight, 18.5-24.9 – normal, 25-29.9 – overweight, 30-34.9 – class I obesity, 35-39.9 – class II obesity, ≥40 – class III obesity. The results are indicative; a doctor’s consultation is required to fully assess your health.

How to reduce your body mass index to a normal value?

To reduce BMI to a normal value (18.5-24.9), it is necessary to create a calorie deficit: eat right, increase physical activity, and lead a healthy lifestyle. It is recommended to lose weight gradually - 0.5-1 kg per week. Consulting a nutritionist will help you create a plan.

How to increase body mass index if you are underweight?

To increase BMI if you are underweight (<18.5), you need to increase your caloric intake, include more proteins and carbohydrates, eat regularly, and increase muscle mass through strength training. Consulting a doctor will help rule out medical causes of low weight.

What is the difference between body mass index and waist-height index?

BMI evaluates overall body weight relative to height, while the waist-height index (WHI) takes into account fat distribution—the ratio of waist circumference to height. The TRI better reflects abdominal obesity and the risk of metabolic diseases. Both indicators complement each other.

Can you trust an online BMI calculator?

Yes, our online BMI calculator uses the standard WHO formula for calculating BMI and gives accurate results. However, remember that BMI is a guideline and does not replace consultation with a doctor for a complete assessment of your health.

What is the normal body mass index for teenagers?

For teenagers, special percentile charts are used taking into account gender and age. Normal values ​​change as you grow. Typically, a BMI in the range of 13-85 percentile is considered normal, but a pediatrician will give an accurate estimate using age tables.

How to calculate body mass index in pounds and inches?

To calculate BMI in pounds and inches, use the formula: BMI = (weight in pounds × 703) / (height in inches)². For example, if you weigh 150 pounds and are 70 inches tall: BMI = (150 × 703) / (70)² = 21.5. Our calculator supports the metric system (kg and cm).

Does body mass index affect life expectancy?

Research shows that a BMI in the range of 20-25 is associated with the longest life expectancy. BMI <18.5 and >30 increase the risk of premature death. Maintaining a normal BMI through healthy eating and activity promotes longevity.

How to calculate body mass index for weight loss?

To calculate your target weight when losing weight, determine your desired BMI (usually 22-23) and calculate your target weight: weight = BMI × height². The difference between your current and target weight is the number of kilograms to lose. Reduce weight gradually - 0.5-1 kg per week.

What body mass index is considered healthy for older adults?

For older people (over 65 years old), the acceptable BMI range may be slightly higher - 23-28. Being slightly overweight may be a protective factor. However, exact recommendations depend on individual health and should be discussed with your doctor.

Can body mass index be used to assess diabetes risk?

BMI is one of the risk factors for type 2 diabetes. A BMI ≥25 increases the risk of diabetes, and a BMI ≥30 increases the risk significantly. However, heredity, lifestyle and other factors are also important for a full assessment. Use BMI as a guide.

How is body mass index related to metabolic syndrome?

A BMI ≥25, especially in combination with high blood pressure, high blood sugar and lipid disorders, may indicate metabolic syndrome. This condition increases the risk of cardiovascular disease. Normalizing your BMI through diet and physical activity helps improve your metabolism.