An adjustable-rate mortgage (ARM) is a loan that offers an initial period of fixed interest that then resets at a specified interval. Typically, you'll see an ARM expressed as two numbers. For example, a 5/1 ARM has a fixed interest rate for the first 5 years that then adjusts based on market rates every year after that. An ARM tends to have a lower initial interest rate than a fixed-rate mortgage. However, it does come with a certain amount of unpredictability. That's because when an ARM enters its adjustable period, its interest rate may trend up or down depending on the state of the market. Click here to get pre-approved and see what kind of adjustable rates you may be pre-approved for.