Prime rate

The prime rate or prime lending rate is an interest rate used by banks, typically representing the rate at which they lend to their most creditworthy customers. Some variable interest rates may be expressed as a percentage above or below prime rate.

The prime rate is used often as an index in calculating rate changes to adjustable-rate mortgages (ARM) and other variable rate short-term loans. It is used in the calculation of some private student loans. Many credit cards and home equity lines of credit with variable interest rates have their rate specified as the prime rate (index) plus a fixed value commonly called the spread or margin.