Calculate your Body Mass Index (BMI) instantly using metric or imperial measurements. Compare your result against internationally recognized BMI classifications, discover your healthy weight range, and understand how your BMI relates to overall health and wellness.
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336 × 280 — Ad Zone B
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BMI Scale
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Underweight
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Overweight
Obese I
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Your BMI
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kg/m²
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Body Fat Est.
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Deurenberg formula
Ideal Weight Range for Your Height
Healthy BMI (18.5 – 24.9)
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Your weight
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Estimated Body Fat %
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Estimated using the Deurenberg formula (BMI, age, sex). This is an approximation — DEXA scan is the gold standard.
Medical Disclaimer: BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, age-related changes, or fat distribution. Always consult a qualified healthcare professional before making decisions about your health.
Body Mass Index (BMI) is a standardized screening measurement that estimates body fat by dividing a person's weight in kilograms by the square of their height in metres (kg/m²). Developed by Belgian statistician Adolphe Quetelet in 1832 and later adopted by the World Health Organization, BMI classifies adults into four primary weight-status categories — underweight, normal weight, overweight, and obese — and is used globally by clinicians, public-health researchers, and fitness professionals as a rapid, equipment-free indicator of weight-related health risk.
What Is BMI (Body Mass Index)?
Body Mass Index (BMI) is a standardized screening measurement used worldwide to assess whether a person's weight falls within a healthy range relative to their height. Healthcare providers, researchers, and public health organizations commonly use BMI as a quick method for identifying potential weight-related health risks.
The BMI system was originally developed in 1832 by Belgian mathematician and statistician Adolphe Quetelet and was later adopted by modern medical organizations as a practical population-level health screening tool. Today, BMI remains one of the most widely used anthropometric measurements globally.
The calculation compares body weight to height and produces a numerical value that falls into a recognized BMI classification range. The result helps determine whether an individual is underweight, normal weight, overweight, or obese according to international health guidelines.
Standard Adult BMI Categories
According to the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC), BMI classifications for adults aged 20 years and older are interpreted using the following ranges:
Underweight: Below 18.5
Normal Weight: 18.5 – 24.9
Overweight: 25.0 – 29.9
Obesity Class I: 30.0 – 34.9
Obesity Class II: 35.0 – 39.9
Obesity Class III: 40.0 and above
What Is Considered a Healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is considered the healthy range. Individuals within this range generally experience lower risk levels for conditions associated with excess or insufficient body weight. However, BMI should always be interpreted alongside other health indicators such as waist circumference, body fat percentage, physical activity levels, and overall medical history.
BMI Calculator for Men and Women
The BMI formula itself is identical for men and women. However, body composition can vary significantly between sexes. Women naturally carry a higher percentage of body fat than men at the same BMI value, while men often carry greater lean muscle mass. For this reason, BMI should be viewed as a screening tool rather than a complete assessment of body composition.
BMI Limitations
Although BMI is useful for large-scale health screening, it does have limitations. It does not distinguish between fat mass and muscle mass, meaning athletes and highly muscular individuals may receive elevated BMI scores despite having healthy body fat levels.
BMI also does not account for age-related body composition changes, bone density differences, pregnancy, or fat distribution throughout the body. Healthcare professionals often combine BMI with additional measurements to obtain a more comprehensive health assessment.
BMI and Different Ethnic Populations
Research has shown that certain ethnic populations may experience health risks at lower BMI levels than others. Some Asian populations, for example, may develop obesity-related conditions such as type 2 diabetes and cardiovascular disease at BMI values below traditional international thresholds. Because of this, several countries have adopted modified BMI guidance for specific populations.
Why BMI Is Still Widely Used
Despite its limitations, BMI remains one of the fastest, simplest, and most accessible health screening methods available. It requires only height and weight measurements, making it useful for personal health tracking, clinical screening, epidemiological research, and public health monitoring worldwide.
Frequently Asked Questions
What is BMI?
BMI stands for Body Mass Index. It is a numerical value calculated using a person's height and weight to estimate whether they fall within a healthy weight range. BMI is commonly used as a screening tool for potential weight-related health risks.
What is a healthy BMI range?
For most adults, a healthy BMI falls between 18.5 and 24.9. A BMI below 18.5 is considered underweight, 25 to 29.9 is considered overweight, and 30 or above is classified as obesity.
How is BMI calculated?
BMI is calculated by dividing weight in kilograms by height in meters squared. For imperial units, BMI equals weight in pounds multiplied by 703 and divided by height in inches squared.
Is BMI accurate?
BMI is useful as a screening tool but is not a direct measure of body fat. It does not distinguish between muscle, bone, and fat mass. Athletes and highly muscular individuals may have elevated BMI values despite having healthy body composition.
What is the ideal weight for my height?
The BMI formula is the same for men and women. However, women generally carry a higher percentage of body fat than men at the same BMI value, which can affect interpretation.
What BMI is considered overweight?
A BMI between 25.0 and 29.9 is classified as overweight according to WHO and CDC guidelines.
What BMI is considered obese?
A BMI of 30 or greater is classified as obesity. Obesity is further divided into Class I, Class II, and Class III categories based on severity.
Can BMI be used for children?
Children and teenagers use age-specific and sex-specific BMI percentile charts rather than standard adult BMI categories. Adult BMI classifications should not be applied directly to children.
Methodology & Sources: BMI calculated using the standard WHO formula. Body fat estimated using the Deurenberg et al. formula (1991): BF% = (1.20 × BMI) + (0.23 × age) − (10.8 × sex) − 5.4, where sex = 1 for male, 0 for female. WHO BMI classification thresholds sourced from the WHO Global Database on Body Mass Index. Body fat healthy range references from the American Council on Exercise (ACE). This tool is for informational purposes only and does not constitute medical advice. Last updated: May 2026.