ARMs vs. Fixed-Rate Mortgages: How to Compare

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Choosing a mortgage is complicated. One of the first choices you’ll make is also one of the most consequential — fixed-rate or adjustable-rate? 

Your decision will impact not only your monthly payment but how long it takes you to pay off your mortgage and how much interest you’ll pay along the way.

An adjustable-rate mortgage, or ARM, can be a better choice in very specific circumstances. But with current interest rates at record low levels this year, a fixed-rate mortgage is the clear winner for most borrowers right now.

Differences Between Fixed-Rate and Adjustable-Rate Mortgages

The most important difference between fixed-rate mortgages and ARMs is straightforward. A fixed-rate mortgage has a mortgage interest rate that doesn’t change. An adjustable-rate mortgage’s interest rate changes at predetermined times, up to limits outlined in the loan’s fine print.

An ARM’s rate will reset on different timelines depending on the loan. The interest rate adjustment schedule is shown as a fraction. The first number in the fraction is when the rate initially resets, and the second number is how frequently it changes after the first adjustment. So a 5/1 ARM has a fixed rate for five years, and then the rate adjusts annually afterward. Typically, an ARM is a 30-year mortgage.

A fixed-rate mortgage is more straightforward than its variable rate counterpart. The main difference you’ll find with fixed-rate loans is in the amortization schedule or loan terms. Just like with ARMs, there are 30-year fixed-rate mortgages. But you can also choose shorter terms, like 10 years or 15 years. 

Pro Tip

With a fixed-rate mortgage you can opt for shorter terms. You’ll have a bigger monthly payment, you’ll pay off your mortgage much more quickly.

Pros and Cons of a Fixed-Rate Mortgage

Fixed interest rate won’t change based on the marketInterest rate may be higher than the introductory interest rate offered by ARM
Typically offers both 30-year and 15-year loan termsIf market interest rates decrease, you’ll need to go through the process and cost of refinancing to take advantage of lower interest rates
More stability

Pros and Cons of an ARM

Introductory rates can be lower than fixed mortgage ratesChanges in market interest rate could change your monthly payment
Future rate adjustment won’t affect you if you plan to sell your house before the introductory period endsLess stability
Typically only offers 30-year loan terms

Interest on ARMs vs. Fixed-Rate Mortgages

Calculating the exact difference in interest on an ARM vs. fixed-rate mortgage over the life of the loan is difficult since it’s impossible to predict how rates may change 10, 20, or even 30 years from now. But one thing you can compare is the interest rate and monthly payments for the introductory period, where the rate remains fixed.

For our example, let’s look at a $347,500 house (the median sales price of houses sold in the U.S. in 2021) with a 20% down payment. This is how much it would currently cost with a 30-year fixed and 5/1 ARM over the introductory period:

30-year fixed5/1 ARM 
Interest rate3.130%3.330%
Monthly payment (not included taxes and other fees)$1,191$1,222
Total interest paid at the end of the 5-year introductory period$41,890$44,640

After the introductory period, the costs become harder to predict since the interest rate will change every year. If the interest rate increases from the original rate, then the monthly payment will increase. If the interest rate decreases from the original rate, then the monthly payment will decrease. 

Is an ARM or Fixed-Rate Mortgage Better?

Choosing between an ARM and a fixed-rate mortgage is all about risk versus reward. With a fixed-rate mortgage, the borrower locks in a rate for the life of the mortgage. With an adjustable-rate, the borrower takes on the risk of their rate rising in the future. In exchange for the increased risk, the borrower typically gets a lower starting interest rate. 

Whether an ARM or fixed-rate mortgage is better depends on your individual financial situation, goals, and tolerance for risk. For most people, the chance of getting a slightly lower interest rate up front isn’t worth the instability of an ARM or the risk of significantly increased costs in the future. This is especially true in the current rate environment, where low rates across the board mean that the difference between fixed and ARM rates may be minor. 

Also, with a fixed-rate mortgage, you have the flexibility to choose a shorter repayment term, like a 15-year loan. Compared to a 30-year mortgage, a 15-year home loan will have a lower interest rate but higher monthly payments. You may potentially pay more per month, but borrowers are willing to do this to pay off the debt faster and save thousands of dollars in interest payments over the life of the loan, says Nadia Alcide, a mortgage professional with Mortgage Biz of Florida. And the option to take a shorter term mortgage isn’t typically available with an ARM.

Still, there are certain situations when an ARM can make sense if it represents significant savings over a fixed-rate loan. These include: 

If You’re Not Keeping the Loan Long Term

Many people’s careers allow them to expect and plan to relocate every so often. For people in this position, an ARM could be a cheaper option than a fixed-rate mortgage. Especially if you know you’ll have to move in the next 5-10 years.

But even in this circumstance, you’ll want to run the numbers. With an ARM, you’re still responsible for closing costs. Closing costs can be 2%-6% of the loan amount, and for an average home that’s thousands of dollars you’ll pay upfront. If you’re only going to be in the home for a year or two it might be cheaper to rent than buy with any type of mortgage. 

If You Can Put the Extra Savings to Work for You

When the monthly savings of an ARM are significant, you may be able to put the extra savings to work.

The introductory period of an adjustable-rate mortgage – when the rate is at its lowest – can be an opportunity to increase your retirement savings or to build your emergency fund. You could also take the money you’re saving and pay down your principal. 

If you plan to pay off your mortgage in 10 years, an ARM with a 10-year introductory rate might be able to help you do that more easily. The extra equity you build can make it easier for you to refinance or save by waiving your private mortgage insurance requirement sooner. 

There is a caveat to this approach: you need to be in a situation where if your rate increases, you can afford it. You can plan for this upfront because an ARM has limits on how much the rate can increase at one time or over the life of the loan. If at any point you consider an ARM, make sure to ask your lender about these limits.

If You’re Taking Out a Jumbo Loan

Jumbo loans are non-conforming loans because they exceed the dollar amount set by Fannie Mae and Freddie Mac. For 2022, the jumbo loan limit is $647,800 for most of the country, but it can be up to 150% higher in areas where homes are more expensive. 

Because jumbo loans aren’t guaranteed by the government, they are riskier for lenders and have stricter underwriting guidelines. This is why jumbo loans also have higher interest rates compared to conforming loans. 

Because of these higher rates, the spread between jumbo ARMs and fixed-rate loans can be more significant than with conforming loans. So you could save more during the introductory-rate period, but jumbo loans are, by definition, bigger loans. So any future rate increase on a jumbo ARM will have a bigger impact on your monthly budget.

If Your Income Is Going to Increase

There are some situations where an ARM can make sense for high net worth or higher-income households, says Greg McBride, chief financial analyst at If you’re expecting a big increase in income, then an ARM might make sense for you. A doctor finishing their residency is a good example. 

The lower payment on an adjustable-rate can offer flexibility if your income is variable or seasonal, he says. But again, he emphasized this only works in extreme cases, for example, athletes or entertainers.

The Bottom Line: ARM vs. Fixed

Right now, the difference in starting rates for adjustable mortgages is minimal to nonexistent relative to a fixed-rate loan, explains McBride. “If you’re not getting any benefit but still shouldering the same amount of risk, why bother?” 

For ARMs to make more sense for people, the spread between fixed-rate and adjustable-rate mortgages would need to increase, which is more likely to happen when interest rates increase overall. Although interest rates have slowly begun to rise from the rock bottom levels of the pandemics, experts predict that rates will remain relatively low for some time. 

The current economic outlook only adds to the ARM’s dwindling appeal. One situation where ARMs traditionally have made sense is when you plan on selling the property before the rate resets. This strategy relies on housing prices rising or at least staying stable. 

While home prices have increased in many areas, driven by record-low mortgage rates and low housing inventory, no one can guarantee this will continue in the long term. And if there’s one thing the COVID-19 pandemic has taught us, it’s the importance of planning for future uncertainty. So, if you’re in a position to afford a home or to refinance, locking in a fixed rate is the way to go in most cases.