Mortgage with a rate that can reset after an initial fixed period.
Adjustable-rate mortgage (ARM) is a mortgage that usually begins with an initial fixed-rate period and then allows the interest rate to change later according to the loan’s adjustment terms.
ARMs matter because they can offer a lower starting payment than a comparable fixed-rate mortgage, but that lower entry cost comes with future rate and payment uncertainty.
For some borrowers, that tradeoff may fit the plan. For others, it introduces risk that matters more than the initial savings. The key is understanding that an ARM is not simply “cheaper.” It is cheaper only if the future adjustment risk stays manageable.
Borrowers usually confront the ARM decision while shopping and comparing rate quotes. It becomes especially relevant when a buyer expects to move, refinance, or pay down the loan before the initial fixed period ends. Common quote labels such as 3/1 ARM, 5/1 ARM, 5/6 ARM, 7/1 ARM, 7/6 ARM, 10/1 ARM, and 10/6 ARM are examples of Hybrid ARM structures.
The ARM structure is then spelled out in closing documents so the borrower understands when the rate can change and what those changes could do to the payment.
Later, if the rate is actually changing, the borrower usually focuses less on the general ARM definition and more on the ARM Reset and the ARM Adjustment Notice showing the new payment.
| ARM label | Initial fixed period | Later adjustment rhythm |
|---|---|---|
| 3/1 ARM | 3 years | Usually annual |
| 5/1 ARM | 5 years | Usually annual |
| 5/6 ARM | 5 years | Usually every six months |
| 7/1 ARM | 7 years | Usually annual |
| 7/6 ARM | 7 years | Usually every six months |
| 10/1 ARM | 10 years | Usually annual |
| 10/6 ARM | 10 years | Usually every six months |
A buyer expects to stay in a home for only a few years and chooses an ARM with a lower starting rate than a fixed-rate option. That decision may work out well if the borrower sells or refinances before later rate adjustments become painful, but it creates more risk if plans change.
An ARM differs from a Fixed-Rate Mortgage because the fixed-rate mortgage keeps the same rate for the full scheduled term, while the ARM can reset later.
An ARM is also not automatically the same as an Interest-Only Mortgage. Some loans can combine features, but adjustable rate and interest-only are separate concepts. One describes future rate movement. The other describes how the payment is calculated during part of the loan life.