This formula also illustrates the importance of paying off unsecured debt like credit cards sooner rather than later. Interest payable to the bank compounds in the same way. If you want to save a lot of money, use your dollars now to pay off the loan because the same dollar amount won't be worth as much in the future.
The above equation can also be rearranged to solve for the present value of money based on a future value that is needed:
PV = FV / [ 1 + i ] ^ n
This can be useful if you want to calculate what you think the current fair value of a stock is. Another simplified example: Let's say you think a stock will grow 10% a year for the next five years, at which time you would like to be able to sell each share for $50. If your 10%-per-year projection holds true, what is a fair price to pay for the stock today? You can figure it out as follows:
PV = $50 / [ 1 + 0.10 ] ^ 5 = a current fair value of $31.05 per share
Of course, earning interest on money is much more predictable. Stocks and other equity assets don't provide the same consistent return year in and year out, and in some years even lose value. Over time, though, the average annual return is much higher than for interest-bearing accounts and can help you build wealth faster.