Interest is a fee paid on borrowed assets. It is the price paid for the use of borrowed money, or, money earned by deposited funds. Assets that are sometimes lent with interest include money, shares, consumer goods through hire purchase, major assets such as aircraft, and even entire factories in finance lease arrangements. The interest is calculated upon the value of the assets in the
same manner as upon money. Interest can be thought of as "rent of money". When money is deposited in a bank, interest is typically paid to the
depositor as a percentage of the amount deposited; when money is borrowed, interest is typically paid to the
lender as a percentage of the amount owed. The percentage of the principal that is paid as a fee over a certain
period of time (typically one month or year), is called the interest rate.