Suppose that you'd like to retire in 40 years and you want to have a future value of $600000 in a savings account. Also suppose that. your employer makes regular monthly payments into your retirement account. If you can expect an APR of 8% for your account, how much do you need your employer to deposit each month? Employer Contribution = The formulas we have been using assume that the interest rate is constant over the period in question, Over a period of 40 years, though, interest rates can vary widely. To see what difference the interest rate can make, let's assume a constant APR of 2.5% for your retirement account. How much do you need your employer to deposit each month under this assumption? Employer Contribution =