How does a compound interest differ from a simple interest?

Answer 1

Simple interest is interest that is compounded solely on what was originally owed. For example, say you owe $500 at 10% annual interest. This means that at the end of the year, you owe $50 dollars in interest (10% of 500) on top of the $500 you already owe. If you were to not pay it again, at the end of the second year you would owe $550 plus another $50 making the total amount you owe to be $600. No matter how long you wait to pay off the debt it will only increase by $50 every year, since that is 10% of the original amount owed.

Compound interest in interest that is compounded on what what was originally owed PLUS any interest left over. Using the example above if the interest on the original $500 had been compound interest by the second year one would have owed $550 plus an additional $55 dollars in interest (10% of 550). This is the danger of compound interest as it always increases as long as the debt continues to be unpaid.