Glossary: Credit card
Used by the holder to buy goods and services, credit cards also have a monthly or annual spending limit, which may be raised or lowered depending on the creditworthiness of the cardholder. But unlike charge cards, borrowers aren’t forced to pay the balance off in full every month and, as long as they make a stated minimum payment, can carry a balance from one month to the next, generating compound interest. As the issuing company is effectively giving you a short-term loan, most credit cards have variable and relatively high interest rates. Allowing the interest to compound for too long may result in dire financial straits.
This is effectively paying interest on interest. Interest is calculated not only on the initial sum borrowed (principal) or saved (see APR and AER) but also on the accumulated interest. The more frequently interest is added to the principal, the faster the principal grows and the higher the compound interest will be. Compound interest differs from “simple interest” in that simple interest is calculated solely as a percentage of the principal sum.