In today's market, the mortgage rate of a 5-year ARM is a 94 basis points (0.94%) lower than a comparable 30-year fixed. Rates for the 5-year ARM average 2.99% and rates for the 30-year loan average 3.93%. Because its rates are lower, 5-year ARMs save $52 per $100,000 borrowed at today's mortgage rates. Getting access to cheaper payments, though, should not be the reason you choose an adjustable-rate mortgage over a fixed-rate one.