How an ARM reset actually works
A 5/1, 7/1, or 10/1 adjustable-rate mortgage gives you a fixed introductory rate for the first 5, 7, or 10 years. At the end of that period, the rate resets based on an index (commonly SOFR or Treasury yields) plus a fixed margin defined in your loan documents.
After the first reset, the rate adjusts annually for the remainder of the loan. Each adjustment is bounded by your cap structure. Most ARMs use a 2/2/5 structure: maximum 2 percentage points at the first reset, 2 percentage points each year after, and 5 percentage points lifetime over your original rate.
The key practical insight: even in a worst-case scenario, your payment cannot exceed what 5 percentage points above your original rate would generate. The cap structure caps your downside.
Why the lifetime cap matters more than people think
Many homeowners panic at reset and rush to refinance into a fixed rate. The math often says don't.
Consider a homeowner who locked a 4.5% ARM in 2021. At reset, the expected new rate might be 7.5%. Available refinance rates might be 6.5%. The natural reaction is to refinance to lock in the lower fixed rate.
But the worst-case ARM rate under a 5-percentage-point lifetime cap is 9.5%. The expected new rate is 7.5%. Refinancing locks in 6.5% but costs $5,000 to $10,000 in closing costs, and gives up the option that the index drops in future years.
Run the numbers and the answer often becomes: hold the ARM if you'll be in the home less than 5 to 7 more years. The closing costs of refinancing exceed the interest savings over a short hold period.
When refinancing actually wins
Refinancing wins when three things are all true: the gap between expected new ARM rate and available refi rate is at least 1 percentage point; you'll hold the home long enough for the lower rate to recoup closing costs (typically 18 to 30 months minimum); and rate forecasts suggest the index will stay elevated rather than fall.
Recasting is a third option worth considering. If you have a meaningful lump sum (inheritance, sale proceeds, bonus), applying it to the ARM principal reduces the balance, which reduces the payment at the new higher rate. You keep the option value of the ARM while cutting the dollar impact. See our recast calculator for that math.
How to find your expected new rate
Your loan documents specify the index and margin. The new rate is index value plus margin, subject to caps.
Common indexes: 30-day Average SOFR (Secured Overnight Financing Rate), 1-year Constant Maturity Treasury, 11th District Cost of Funds. Each one has different rate behavior; check yours.
Common margins: 2.25% to 2.75%, depending on credit profile and lender.
Your servicer is required by federal regulation to send you a written rate-change notice 60 to 120 days before the reset takes effect. The notice will state the new rate and new payment. If you have not received a notice and your reset is within 60 days, contact your servicer immediately.
What to do now
First, calculate the new payment using your specific numbers. The calculator above lets you input your expected new rate and lifetime cap to see both the typical and worst-case payment scenarios.
Second, compare against the cost of refinancing to a fixed rate, accounting for closing costs and your expected time horizon. If you'll hold more than 5 to 7 years and the rate gap is meaningful, refinancing usually wins. If less, holding the ARM usually wins.
Third, if neither hold-the-ARM nor refinance is appealing, consider whether a lump-sum recast (or partial principal pay-down) would close the affordability gap. Reducing the balance reduces the dollar impact of the higher rate.
Frequently asked questions
When does my ARM reset?
A 5/1 ARM resets after 5 years and then annually. 7/1 resets after 7 years and then annually. 10/1 resets after 10 years. Check your loan documents for your specific reset date.
What is the 2/2/5 cap structure?
Maximum 2 percentage points at the first reset, 2 percentage points each subsequent year, and 5 percentage points lifetime above your original rate.
Should I refinance my ARM before it resets?
Depends on the rate gap, closing costs, and how long you'll keep the home. The calculator runs the math. As a rule, refinancing makes sense when expected new ARM rate is at least 1 percentage point above the available fixed rate AND you'll hold the home at least 24 months.
What if I cannot afford the new payment?
Options: refinance to a lower fixed rate, recast with a lump sum to reduce the balance, request a loan modification from your servicer, or sell the home. Forbearance is generally not the right tool for rate-reset payment shock.