BMI Calculator

Use this free BMI calculator to find your Body Mass Index using either imperial (pounds and inches) or metric (kilograms and centimeters) measurements. Enter your height and weight to instantly calculate your BMI and see which health category you fall into.

How to use this BMI calculator

1. Select your measurement system — Imperial (pounds and inches) or Metric (kilograms and centimeters) using the tabs at the top of the calculator.
2. Enter your weight in pounds or kilograms.
3. Enter your height in inches or centimeters. To convert feet to inches, multiply the number of feet by 12 and add any remaining inches. For example, 5 feet 8 inches = 68 inches.
4. Click Calculate BMI to see your BMI score, health category, and where you fall on the BMI scale.

Frequently asked questions

Q: What is a healthy BMI range?
A: According to the World Health Organization, a BMI between 18.5 and 24.9 is considered normal weight. A BMI below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese. These thresholds apply to adults aged 18 and older. Different standards may apply to children, athletes, and elderly individuals.

Q: Is BMI an accurate measure of health?
A: BMI is a useful screening tool but has well-known limitations. It does not distinguish between muscle mass and fat mass, which means muscular athletes may be classified as overweight despite having low body fat. It also does not account for where fat is distributed in the body, which affects health risk. BMI is best used as a starting point alongside other health metrics such as waist circumference, blood pressure, and cholesterol levels.

Q: How do I convert my height from feet and inches to inches?
A: Multiply the number of feet by 12 and add the remaining inches. For example, 5 feet 4 inches = (5 × 12) + 4 = 64 inches. 5 feet 10 inches = (5 × 12) + 10 = 70 inches.

Q: Does BMI apply to children?
A: Standard BMI calculations are designed for adults aged 18 and older. For children and teenagers aged 2 to 19, BMI is calculated the same way but interpreted differently using age and sex-specific percentile charts from the CDC. A pediatrician should interpret BMI results for anyone under 18.

Q: What should I do if my BMI is outside the normal range?
A: BMI outside the normal range is worth discussing with a healthcare provider, who can assess your overall health picture more completely. For those in the overweight or obese range, modest changes in diet and physical activity can have significant health benefits even without reaching the normal BMI range. Avoid making drastic dietary changes without medical guidance.