| Stage | Rate | Notes |
|---|---|---|
| Years 1 to 5 | 5.5 percent | Fixed introductory rate |
| First adjustment | Up to 7.5 percent | Capped at 2 percent increase |
| Later adjustments | Up to 2 percent more each | Subject to periodic cap |
| Lifetime maximum | 10.5 percent | 5 percent over the start rate |
Glossary · Financing & mortgages
Adjustable-Rate Mortgage (ARM)
An adjustable-rate mortgage, or ARM, has an interest rate that changes over time instead of staying fixed. It usually opens with a lower fixed introductory rate, then adjusts periodically based on a market index plus a set margin. ARMs offer lower early payments in exchange for the risk that the rate rises later.
Also known as: ARM
How does an ARM work?
An ARM is named by two numbers, such as 5/1, meaning the rate is fixed for five years then adjusts once a year. After the intro period, the rate equals a market index plus the lender margin, and caps limit how far it can move each period and over the loan.
During the introductory period, your rate and payment are steady and usually lower than a comparable fixed loan. Once that ends, the rate resets on a set schedule.
At each reset, the lender adds its fixed margin to the current index value. Rate caps restrict the increase per adjustment and across the life of the loan.
Why do rate caps matter on an ARM?
Caps protect borrowers by limiting how much the rate can jump. A typical structure caps the first adjustment, each later adjustment, and the lifetime increase. Without caps, a rising index could push payments to unaffordable levels, so caps define your worst-case cost.
A common cap format is written as three numbers, such as 2/2/5, meaning a 2 percent limit on the first change, 2 percent on later changes, and 5 percent over the loan.
Before choosing an ARM, calculate the payment at the maximum possible rate. If that worst case is unaffordable, the low intro rate is not worth the risk.
When does an ARM make sense?
An ARM can fit buyers who expect to move or refinance before the fixed period ends, or who want lower early payments. The trade-off is uncertainty, because payments can rise sharply once adjustments begin. A fixed-rate loan suits buyers who value predictable payments.
If you are confident you will sell or refinance within the intro period, an ARM lets you capture the lower rate and leave before adjustments hit.
Plans change, though. If you end up keeping the loan past the fixed period, be ready for higher and variable payments.
Worked example. For example, a borrower takes a 5/1 ARM on a 300,000 dollar loan at a 5.5 percent intro rate with 2/2/5 caps. For five years the payment holds steady. At the first adjustment, the index plus margin could raise the rate up to 7.5 percent, and over the loan it could reach a maximum of 10.5 percent, meaningfully increasing the monthly payment.
Common mistakes with Adjustable-Rate Mortgage
- Do not choose an ARM without calculating the payment at the maximum possible rate, because that is your worst-case cost.
- Do not assume you will refinance or move before the adjustment, since plans and market conditions can change.
- Do not ignore the margin, because it is fixed for the life of the loan and drives the rate after each reset.
- Do not confuse the intro rate with a permanent rate, since it only lasts the initial fixed period.
- Do not overlook the caps, because they define how high your rate and payment can legally climb.
Related terms
Term
Fixed-Rate Mortgage
A mortgage with an interest rate that stays the same for the entire loan term.
Define TermDiscount Points
Upfront fees a borrower pays the lender to lower the loan's interest rate.
Define TermConventional Loan
A mortgage not insured or guaranteed by the government, often following Fannie Mae and Fre
Define TermJumbo Loan
A mortgage that exceeds the conforming loan limits set for Fannie Mae and Freddie Mac.
DefineAdjustable-Rate Mortgage FAQ
What does 5/1 ARM mean?
The first number is the years the rate stays fixed, and the second is how often it adjusts afterward. A 5/1 ARM is fixed for five years, then the rate can change once every year based on an index plus margin.
How high can my ARM rate go?
Rate caps set the ceiling. A common 2/2/5 structure limits the first adjustment to 2 percent, later adjustments to 2 percent each, and the lifetime increase to 5 percent above your starting rate. Always confirm your loan's caps.
Is an ARM cheaper than a fixed-rate mortgage?
An ARM usually starts with a lower rate and payment than a comparable fixed loan. That savings only lasts through the intro period, after which the rate can rise, so the long-run cost is uncertain.
What index do ARMs use?
Modern ARMs are commonly tied to a published benchmark such as SOFR, plus a fixed lender margin. Your note names the specific index. When that index moves, your rate moves with it at each scheduled adjustment.
Can I refinance out of an ARM?
Yes, many borrowers refinance an ARM into a fixed-rate loan before or shortly after the first adjustment. Refinancing depends on qualifying again and paying closing costs, and on rates being favorable when you apply.
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