The normal BMI range for women is between 18.5 and 24.9. BMI, or body mass index, is a measure of body composition based on weight and height. It is used to broadly define different weight groups in adults 20 years old or older. A BMI below 18.5 is considered underweight, while a BMI between 25 and 29.9 is considered overweight, and a BMI of 30 or more is considered obese. BMI is a screening measure and is not intended to diagnose disease or illness. It is important to note that BMI has some limitations, as it does not measure body fat specifically.