Calculate the amount of money needed at the time of retirement, to cover the costs of living until the end of life. Please consider the following steps in building this model: take an inventory of all costs you expect a regular person to incur during retirement, during a typical month of the year. fill in the amounts for each one calculate the grand total, for that month calculate the grand total for an entire year choose the number of years you anticipate to live after you retire calculate the total amount of money you require, to live for the rest of your life.