You’ll have more than $102 at the end of five years because your interest will compound over time. In other words, you earn interest on the money you save and on the interest your savings earned in prior years. Here’s how the math works. A savings account with $100 and a 2 percent annual interest rate would earn $2 in interest for an ending balance of $102 by the end of the first year. Applying the same 2 percent interest rate, the $102 would earn $2.04 in the second year for an ending balance of $104.04 at the end of that year. Continuing in this same pattern, the savings account would grow to $110.41 by the end of the fifth year.
The reason you have less is inflation. Inflation is the rate at which the price of goods and services rises. If the annual inflation rate is 2 percent but the savings account only earns 1 percent, the cost of goods and services has outpaced the buying power of the money in the savings account that year. Put another way, your buying power has not kept up with inflation.
Assuming the same interest rate for both loans, you will pay less in interest over the life of a 15-year loan than you would with a 30-year loan because you repay the principal at a faster rate. This also explains why the monthly payment for a 15-year loan is higher. Let’s say you get a 30-year mortgage at 6 percent on a $150,000 home. You will pay $899 a month in principal and interest charges. Over 30 years, you will pay $173,757 in interest alone. But a 15-year mortgage at the same rate will cost you less. You will pay $1,266 each month but only $77,841 in total interest—nearly $100,000 less.
When interest rates rise, bond prices fall. And when interest rates fall, bond prices rise. This is because as interest rates go up, newer bonds come to market paying higher interest yields than older bonds already in the hands of investors, making the older bonds worth less.
In general, investing in a stock mutual fund is less risky than investing in a single stock because mutual funds offer a way to diversify. Diversification means spreading your risk by spreading your investments. With a single stock, all your eggs are in one basket. If the price falls when you sell, you lose money. With a mutual fund that invests in the stocks of dozens (or even hundreds) of companies, you lower the chances that a price decline for any single stock will impact your return. Diversification generally may result in a more consistent performance in different market conditions.