BMI Calculator - Know Your Body Mass Index
Calculate your Body Mass Index instantly using height and weight. Understand what your BMI means for your health.
01Calculate Your BMI
What Is BMI?
Body Mass Index (BMI) is a simple numerical measurement derived from a person's height and weight. It was developed in the 19th century by Belgian statistician Adolphe Quetelet and is widely used today as a quick screening tool to categorise individuals into weight groups such as underweight, normal, overweight, or obese.
While BMI is not a direct measure of body fat, research has shown a strong correlation between BMI and body fat across populations. It is commonly used by healthcare professionals, insurance companies, and public health organisations as an initial indicator of potential health risks associated with weight.
How Is BMI Calculated?
BMI is calculated using a straightforward formula that divides your weight by the square of your height. The result gives you a single number that places you in a standard health category.
BMI = weight (kg) ÷ height² (m²)
For example, if your weight is 70 kg and your height is 1.75 m, your BMI would be 70 ÷ (1.75 × 1.75) = 22.9, which falls in the Normal Weight range. In imperial units, the formula includes a conversion factor of 703.
BMI Categories
< 18.5
Underweight
18.5–24.9
Normal Weight
25–29.9
Overweight
≥ 30
Obese
Limitations of BMI
BMI does not differentiate between muscle mass and body fat — athletes may have a high BMI despite being very fit.
It does not account for age, gender, bone density, or body composition, which all influence healthy weight.
BMI may underestimate body fat in elderly individuals and overestimate it in muscular individuals.
It does not consider where fat is distributed on the body, which is also an important health indicator.
Tips For A Healthy BMI
Maintain a balanced diet rich in fruits, vegetables, whole grains, and lean proteins to support a healthy weight.
Exercise regularly — aim for at least 150 minutes of moderate activity or 75 minutes of vigorous activity per week.
Stay hydrated throughout the day. Drinking enough water supports metabolism and overall health.
Get 7–9 hours of quality sleep each night. Poor sleep is linked to weight gain and hormonal imbalances.
Limit excessive sugar, processed foods, and high-calorie snacks to keep your calorie intake in check.