BMI Calculator
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18.5-24.9
25-29.9
≥30
Step-by-Step Calculation
About BMI and Health
Body Mass Index (BMI) is a standardized measure to evaluate a person's body weight relative to height. It helps in identifying whether an individual is underweight, normal weight, overweight, or obese. BMI is calculated using weight and height measurements, and it is widely used because it is easy, quick, and inexpensive.
The BMI formula in metric units is: BMI = Weight (kg) ÷ [Height (m)]². For imperial units, the formula is: BMI = (Weight (lbs) × 703) ÷ [Height (in)]². The result gives a numeric value which can then be categorized into a standard range.
It is important to understand that BMI does not measure body fat directly but is correlated with body fat levels. Individuals with high muscle mass may have higher BMI even if body fat is low. Conversely, older adults or individuals with low muscle mass may have low BMI but higher body fat percentage.
BMI categories for adults are:
- Underweight: BMI less than 18.5
- Normal weight: BMI 18.5–24.9
- Overweight: BMI 25–29.9
- Obese: BMI 30 or higher
Maintaining a BMI in the normal range is generally associated with lower risk for chronic diseases like heart disease, diabetes, and hypertension. BMI can also help track changes over time and evaluate the effectiveness of dietary and lifestyle interventions.
Children and teenagers have age-specific BMI ranges called BMI-for-age percentiles. These take into account growth patterns and development, and are interpreted differently than adult BMI.
Healthy lifestyle practices such as balanced nutrition, regular physical activity, sufficient sleep, and stress management can positively impact BMI and overall health. A healthcare professional can provide personalized guidance if your BMI is outside the healthy range.
This tool provides step-by-step calculations to help you understand how BMI is derived and visualizes your health status using charts and scales. Use the insights responsibly and consult a medical professional for detailed assessments.