You may have a higher-than-average mortgage rate for a number of reasons. Credit scores, loan terms, interest rate types (fixed or adjustable), down payment size, home location and loan size will all affect the rate offered to individual home shoppers. One of the best ways to lower your rate is to improve your credit score. Different mortgage lenders offer different rates. It's estimated that about half of all buyers only look at one lender, primarily because they tend to trust referrals from their real estate agent. But shopping around for a lender will help you snag the lowest rate out there.