Adjustable-Rate Mortgages Look More Appealing Than Ever. Are They Worth It?

Surging mortgage rates have resurfaced an old question for homebuyers: How much risk is a cheaper monthly payment worth?

In the final week of September, the average rate on a 30-year fixed mortgage climbed to 7.30%—its highest level since November 2023, according to the Mortgage Bankers Association. The average rate on a 5/1 adjustable-rate mortgage (ARM), meanwhile, was 6.47%.

On a $400,000 home with 20% down, that would cut the initial principal-and-interest payment by about $178 a month—enough to make the difference between buying or staying on the sidelines, according to Hannah Jones, senior economist at Realtor.com®.

“A buyer who can't afford a 30-year fixed-rate mortgage at 7% but can make payments on a 5/6 ARM at 6% may be priced out of fixed-rate borrowing entirely,” she says. “Increasingly, it may simply be the only way some buyers can enter the market at all.”

And as the discount has widened, more borrowers have taken it. ARMs accounted for 10.3% of mortgage applications in late September, up from 7% at the beginning of the year and the highest share since October 2025.

But the lower payment comes with a catch: Once the initial fixed period ends, the rate can rise—potentially outpacing what a borrower would have paid on the fixed-rate mortgage they passed up.

As more buyers turn to ARMs for relief, the question is becoming harder to avoid: Is the cheaper upfront payment worth the risk of paying more in the long run?

How adjustable-rate mortgages work

As the name suggests, the interest rate on an adjustable-rate mortgage can change over time.

The structures can vary depending on the loan type, but the most common versions today typically start with a rate that is fixed for five years. After that, it resets at regular intervals. A 5/1 ARM adjusts once a year, while a 5/6 ARM adjusts every six months.

At each reset, the lender adds a fixed margin to a market index. A borrower’s rate could fall at that point, but it could also rise.

In exchange for accepting that risk, borrowers get a lower starting rate than they would on a traditional 30-year fixed mortgage. The trade-off has repeatedly driven borrowers toward ARMs when fixed rates became especially expensive.

In 1981, the average 30-year fixed mortgage rate reached a record 18.63%. By mid-1984, ARMs had grown from a small share of the market to nearly two-thirds of conventional home purchase loans, as the gap between fixed and adjustable rates reached more than 2 percentage points.

They surged again during the housing boom. ARMs accounted for 34% of single-family mortgages originated in 2004, the highest share since 1994.

What happened next made ARMs synonymous with the financial crisis for many Americans. And while the association isn't entirely wrong, it may still be misleading.

In early 2007, the typical subprime ARM reaching its first reset jumped from about 7% to 9.5%, according to the Federal Reserve. That increased the typical borrower's monthly payment by 25% to 30%, or about $350—nearly $580 in today's dollars.

By the end of that year, more than one-fifth of subprime ARMs were seriously delinquent, even though they represented only about 7% of outstanding first-lien mortgages.

But many troubled borrowers defaulted before their rates ever changed. Falling home prices, high leverage, and deteriorating underwriting standards all played major roles.

And today's mainstream ARMs operate under very different rules. Critically, lenders generally can't qualify borrowers based only on a temporary teaser rate if the loan could later reset higher.

Why the discount matters

The risk that an ARM could reset higher is only half of the calculation. The other is how much borrowers save in exchange for taking that risk.

That makes the gap between fixed and adjustable rates a critical part of determining whether an ARM is worth it.

At the beginning of 2026, MBA reported an average 30-year fixed rate of 6.18% and an average 5/1 ARM rate of 5.42%, a 76-basis-point difference. By late September, both rates had risen, but the gap had widened to 83 basis points.

The wider the gap, the more a borrower saves each month during the fixed period—and the larger the cushion they can build before the ARM resets. A smaller gap means taking the same future rate risk for less savings upfront.

And that discount changes with market conditions.

One important driver of that gap is the yield curve. Fixed mortgages are more closely tied to longer-term interest rates, while ARM pricing depends more heavily on shorter-term rates. When longer-term rates rise relative to shorter-term rates, ARMs can become cheaper by comparison.

But the yield curve isn't the whole story. Demand for mortgage-backed securities, Federal Reserve intervention, guarantee fees, and lenders' own funding costs and margins can all push fixed and ARM rates further apart—or closer together.

The aftermath of the financial crisis offers a striking example.

In 2009, the yield curve was steep, which ordinarily would have made ARMs substantially cheaper. But massive Federal Reserve purchases of agency mortgage-backed securities helped push fixed mortgage rates down, shrinking the ARM discount.

For borrowers, the importance of those market forces boils down to a much simpler question: How much of a head start does today's discount actually buy?

On a $320,000 mortgage, the fixed loan at 7.30% starts around $2,194 a month. At 6.47%, the ARM starts around $2,016, saving about $178 a month.

MBA also reported higher points and origination fees on the ARM: 1.20 points versus 0.75, a difference equivalent to about $1,440 on a $320,000 loan.

Even after accounting for that extra upfront cost, the ARM borrower makes about $10,650 less in monthly payments and owes roughly $2,700 less on the mortgage over the first five years of the mortgage.

And by the time the rate can first reset, the ARM borrower is about $11,900 ahead.

How high could the payment go?

The question then becomes how long that cushion lasts after rates reset.

“No one can tell the future, but the terms of your loan are spelled out clearly,” Jones says.

Consider an illustrative 5/6 ARM with a 2/1/5 cap structure: The rate is fixed for five years. At the first adjustment, it can rise by no more than 2 percentage points. Every six months after that, it can rise by no more than 1 point, with a lifetime increase capped at 5 points.

Those caps put a ceiling on the interest rate—and allow borrowers to calculate both how high their payment could climb and how quickly their head start could run out.

In a worst-case scenario, where rates rise as fast as the cap structure allows, a 6.47% ARM could jump to 8.47% after five years, then 9.47%, 10.47%, and eventually its 11.47% lifetime ceiling.

At those rates, the monthly principal-and-interest payment would rise from about $2,016 initially to roughly $2,405 at the first reset, then $2,608, $2,814, and ultimately $3,023 at the lifetime maximum.

It's a punishing path to be sure, but even then, the ARM's accumulated savings last until six years and nine months after closing—about 21 months after the first reset.

A more moderate scenario might see rates both rise and fall before eventually reaching 8.47%. Under that path, the ARM remains ahead until just after Year 10.

That gives borrowers two important numbers to weigh against their own plans: How high their payment could jump, and how long their savings could survive. But it's the first number that's the most important, according to Jones.

“Can your budget absorb a significant jump in your monthly mortgage payment?” she says. “If not, the ARM may not be the right product for you.”

Are ARMs worth it today?

Her point is an important one because timing—how long someone may or may not be able to endure those higher payments—is the last piece of the calculation.

An ARM can work as a strategy for someone who expects to sell or refinance before higher payments eat through the savings built up earlier. But that strategy is far safer if the borrower could still afford the loan if those plans fall through.

And Americans are staying in their homes longer. From 2000 through 2008, the typical seller had owned their home for about six years, according to the National Association of Realtors®. By 2025, median seller tenure had reached a record 11 years.

That trend raises the odds that an ARM borrower could still have the loan after the fixed period ends, when higher payments can begin eating into the savings built up earlier. And while refinancing is always an option, it's just as a conditional one as selling is.

“Borrowers should assume refinancing is not guaranteed and price their ARM decision accordingly,” Jones says.

Any new loan with a lower rate has to save enough to outweigh closing costs, and borrowers still have to qualify based on their finances and home value.

So deciding whether an ARM is worth it comes down to three questions: How large is the discount? How long will its savings survive if rates rise? And how likely are you to still have the mortgage when they run out?