Use this free BMI calculator to quickly determine your Body Mass Index based on your weight and height. The tool instantly shows your BMI value, category, a color-coded visual gauge, and the healthy weight range for your height. It also highlights the WHO-recommended Asian and Indian BMI cutoffs, which differ from the standard Western thresholds due to differences in body composition and metabolic risk.
Last updated: March 2026
BMI (Body Mass Index) is calculated using a simple formula that relates your weight to the square of your height:
Example: A person weighing 70 kg with a height of 170 cm (1.70 m) would have a BMI calculated as follows:
A BMI of 24.22 falls within the “Normal weight” category according to the standard WHO classification (18.5 to 24.9). However, under the Asian/Indian cutoffs recommended by WHO, this would be considered “Overweight” since the threshold is lowered to 23 for Asian populations.
The World Health Organization (WHO) classifies BMI into the following categories. Each range carries different levels of health risk:
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Nutritional deficiency, weakened immunity, bone loss |
| 18.5 – 24.9 | Normal weight | Lowest risk; maintain through balanced diet and exercise |
| 25.0 – 29.9 | Overweight | Increased risk of heart disease, high blood pressure, type 2 diabetes |
| 30.0 – 34.9 | Obese Class I | High risk of cardiovascular disease, diabetes, sleep apnea |
| 35.0 – 39.9 | Obese Class II | Very high risk; significant impact on mobility and quality of life |
| 40.0 and above | Obese Class III | Extremely high risk; severe health complications likely |
Studies have consistently shown that Indians develop insulin resistance, diabetes, and heart disease at BMI levels considered “normal” by Western standards. The Indian Council of Medical Research (ICMR) and several cardiological societies in India support using these revised cutoffs for better health screening. If you are of South Asian descent, consider a BMI below 23 as the target for optimal health.
| BMI Range | Standard (WHO) | Asian/Indian Cutoff |
|---|---|---|
| Below 18.5 | Underweight | Underweight |
| 18.5 – 22.9 | Normal | Normal |
| 23.0 – 24.9 | Normal | Overweight |
| 25.0 – 29.9 | Overweight | Obese |
| 30.0+ | Obese | Severely Obese |
Regardless of your current BMI, adopting the following habits can help you achieve and maintain a healthy body weight:
BMI (Body Mass Index) is a numerical value derived from your weight and height using the formula: weight in kilograms divided by the square of height in meters. It was devised in the 19th century by Belgian mathematician Adolphe Quetelet as a quick way to assess whether a person’s weight is proportional to their height. Today, it is used globally as an initial screening tool for weight-related health risks.
BMI is a useful population-level screening tool, but it has limitations at the individual level. It does not differentiate between muscle mass and fat mass, which means a muscular athlete may be classified as overweight or obese despite having low body fat. Similarly, an older person with reduced muscle mass may have a normal BMI but carry excess fat. For a comprehensive health assessment, BMI should be combined with waist circumference measurements, body fat analysis, and clinical evaluation.
The WHO recommends lower BMI thresholds for Asian and South Asian populations. For Indians, overweight is classified as a BMI of 23 or above, and obesity begins at a BMI of 25 or above. These lower cutoffs account for the fact that South Asians tend to develop metabolic complications such as insulin resistance, type 2 diabetes, and cardiovascular disease at lower BMI values compared to Western populations. Multiple studies conducted in India have confirmed these risks.
The standard healthy BMI range is 18.5 to 24.9 according to the WHO. For Asian and Indian individuals, a BMI between 18.5 and 22.9 is considered optimal. Maintaining your BMI within the healthy range is associated with lower risk of chronic diseases, better energy levels, improved mental health, and longer life expectancy. If your BMI falls outside the healthy range, consult a healthcare professional for personalized guidance.
BMI is an indirect measure based on weight and height, while body fat percentage directly measures the proportion of your body that is fat tissue. Two individuals with identical BMI values can have vastly different body fat percentages depending on their muscle mass, bone density, and body composition. Body fat percentage is measured using techniques like DEXA scans, bioelectrical impedance analysis, hydrostatic weighing, or skinfold calipers. For most people, BMI serves as a reasonable approximation, but athletes and highly muscular individuals should rely on body fat measurements instead.
BMI has several well-documented limitations. It cannot distinguish between fat and muscle, does not indicate where fat is distributed in the body (visceral fat around organs is more dangerous than subcutaneous fat), does not account for differences in body composition between men and women, and may be less reliable for children, the elderly, pregnant women, and athletes. Despite these shortcomings, it remains a quick, free, and easy screening method that provides a starting point for assessing weight-related health risks.