The term "per capita" is from the Latin phrase meaning "by head". It is a figure that expresses an average of a particular datum for each person in the population being measured. It is useful in assessing the significance of a particular number in a statistical survey. For instance, if there are 10 traffic fatalities in a city of 100,000 people, that is unfortunate, but if there are the same number of fatalities in a town of 100, that indicates a serious problem.
Determine the size of the population you are measuring. This is the total number of people in your group, whether it is residents in a town, employees in a business or other group.
Determine the figure that you seek to calculate the per capita measure for. It may be income, total hours worked, illnesses or other metric. Whatever the metric, make sure the total number you determine applies exclusively to the population being measured.
Divide the metric by the number of people in the population to get your per capita figure. For instance, if 500 citizens in a town earn a total of $12,500,000 in annual salary, the per capita annual income for the town is $25,000.