When you buy a CD, your money is locked in for specified period of time depend on maturities you choose. The maturity simply refers to the amount of time that your money gets tied up in the investment.
Common maturity dates of CDs are one month, three months, six months, one year, three years, and five years. In general, the longer the time period of the CD you choose, the higher the interest you will receive.
However, if you withdraw your money early, you lose a lot of the interest. CD rates also vary from bank to bank. So it is good idea to shop around to find a bank that offers the highest CD rates. You can find information about the latest CD rates on newspaper or on the Internet.