How much the rate will adjust depends on the mortgage index to which the loan is tied. It might rise, or it might go down. Mortgage rate indexes can fluctuate often depending on the economy, market conditions, and other factors. There’s no way to predict how a 5/1 loan’s rate will change, or by how much, so there’s some level of uncertainty after that five-year period expires.

How a 5/1 Mortgage Loan Works

A 5/1 mortgage loan is generally a good choice in two scenarios. You’ll save big by getting a 5/1 loan rather than a 30-year fixed mortgage if you don’t plan to stay in the home very long. If you’re fairly sure that a career change or a move is in the cards before your five-year fixed period is up, for example, this might be the right option for you. You might also want to consider a 5/1 ARM if you know that you can comfortably afford a little unpredictability when the five-year term expires. You can enjoy a relatively low interest rate for the first five years. If your income is sufficient to cover ebbs and flows in your monthly payment after this time—or to allow you to pay the fees and costs of refinancing—a 5/1 ARM could be a good choice. Some 5/1 ARMs do come with rate caps, so your rate can never increase beyond a certain threshold. These caps help protect you from sky-high payment jumps when your five-year fixed-rate period expires. Otherwise, your monthly interest payments could double or even triple when the interest rate becomes variable.

Types of Hybrid Loans

A 5/1 mortgage loan is only one variation of this mortgage concept. There are also 3/1, 7/1, and 10/1 loans available. They all work on the same premise. The difference lies in that first number. The interest rate on a 3/1 loan will become variable after three years. Likewise, it will become variable after 10 years with a 10/1 ARM.

5/1 Mortgage Loans vs. 30-Year Fixed Loans

The biggest difference between a 5/1 mortgage and a 30-year fixed loan—which many consider to be the “traditional” mortgage product—is that the former can be much more unpredictable. You’ll know exactly how much interest you’ll pay for the life of your mortgage with a 30-year fixed-rate loan, and you’ll have the peace of mind that comes from knowing that your monthly payment won’t increase unless your property taxes or home insurance premiums go up. You only have that peace of mind for the five-year fixed period with a 5/1 mortgage loan. But the biggest advantage of a 5/1 ARM over a 30-year fixed loan is that it comes with a low upfront interest rate, typically much lower than what you’d be offered on a fixed loan. You’ll be making a much smaller monthly payment than you would on a long-term fixed-rate product during the first five years. This can be a big benefit if you’re on a tight budget or otherwise need to keep your housing costs low. But those savings are limited with adjustable-rate mortgages. You can’t count on them for the long haul. You could end up paying significantly more once those five years are up. Consider making use of one of one of the many 5/1 ARM calculators available online to get a realistic idea of what your payments are likely to be and how much they might fluctuate.