First, the Federal Reserve determines a rate called the Federal Funds Rate. The Federal Reserve Bank requires that lenders maintain a percentage of deposits on hand each night. This is called the reserve requirement. Banks will borrow from each other to meet their reserve requirements. When the Federal Funds Rate is high, banks are able to borrow less money and the money they do lend is at a higher rate. When low, banks are more likely to borrow from each other to maintain their reserve requirement. It allows them to borrow more money and the interest rate goes down as well. The interest rates fluctuate with the Federal Funds Rate because it affects the amount of money that can be borrowed. Because money is scarcer, it is more expensive. The US Government requires mortgage lenders to provide their APR through the Truth in Lending Act. It allows consumers to have an apples to apples comparison of what a loan will cost them through different lenders. Keep in mind that lenders may calculate APR differently and APR also assumes you will hold the loan for its full amortization so it is still important to carefully compare and consider when selecting a loan.To put it simply, the mortgage rate is the rate of interest charged on a mortgage. In other words, it is the cost involved in borrowing money for your loan. Think of it as the base cost. Mortgage rates differ from the annual percentage rate (APR). The mortgage rate describes the loan interest only, while APR includes any other costs or fees charged by the lender. The great news is that a little knowledge about the policy and the real effect mortgage shopping has on your credit score provides a great deal of freedom and comfort that helps ensure you make the right mortgage decision.There is no way around credit inquiries when applying for a mortgage. Because credit score is an important determinant that demonstrates a lender's risk, the fact is your credit will be pulled. And, furthermore, the system used to determine that score covers credit inquiries of all different types and taking a hit for line of credit requests just makes sense, whether we like it or not.