In order to determine this sum, we need to consider the compounding of interest and the value time. Compounding means reinvesting the interest earned. This can maximize your returns. The Time Value of Money (TVM), which is a measure of how much an amount would be worth today if it were invested at a specific rate of return, assumes money will have a higher value if received earlier rather than later because inflation decreases the purchasing power of money over time.

Applying these concepts, we can calculate the potential earning by taking into account different factors such as investment duration or rate of compounding. If we reinvest our original deposit and any interest earned after every month/quarter, then our new balance by 18 years should be around $7000.