A BMI calculator is used to estimate body fat but it doesn’t take account for muscle.

This means if you are an athlete or very muscular, you may have a high BMI but not be at health risk.

Those with a lower muscle mass, such as children who have not completed their growth or the elderly who may be losing some muscle mass may have a lower BMI.

During pregnancy and lactation, a woman’s body composition changes, which impacts BMI.

It’s important to take this all in consideration when using a BMI calculator.