IQ = mental age / chronological age x 100

Chronological age is the years you have been alive and health age is the physical age your body is. If you are obese and not in shape for instance or if you smoke a lot, your health age is probably a lot older then your chronological age.

chronological age

It depends on how your chronological age is measured and scored. Often that is described as your intelligence quotient (or IQ).

Chronological age is a person's actual age based on the calendar, while physical age refers to the biological age of a person, which is determined by factors such as overall health, fitness level, and lifestyle habits. Physical age may be younger or older than chronological age depending on how well a person has cared for their body.