# What is BMI?

BMI allows us to compare the health effects of different weights in adults. Body Mass Index (BMI) is simply our current weight (kg) divided by our height (m) squared (weight / height^{2})

To calculate your excess weight, we simply determine the difference in weight needed to lower your BMI into the healthy range (25), for your height.

High quality research^{1,2} over many years involving over 2.5 million adults followed for 10+ years shows that the best health and lowest mortality rates are in people with a BMI between 20 and 24.9. As BMI increases so does the mortality risk which can be calculated as years lost due premature death.