An annuity is a financial product that pays out fixed, regular payments to an individual for income. There are two types of annuities: annuity immediate and annuity due. An annuity immediate makes payments at the end of each payment period, while an annuity due makes payments at the beginning of each period. The present and future value formulas for annuity immediate differ slightly from those of annuity due by a factor of 1+i, the interest rate.