Use a formula to populate B4 with the amount in your retirement account given the annual investment in B2, over the number of years in B1, at the interest rate given in B3. 2. Build a data table to explore potential total savings based on annual contributions from $5,000 to $25,000 in $5,000 increments and using interest rates from 3.0% to 12.0% in 1.0% increments.