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Learning CenterFixed-rate vs. adjustable-rate mortgage: which is right for you?
A fixed-rate mortgage keeps the same rate and principal-and-interest payment for the life of the loan. An ARM starts with a fixed rate for 5, 7, or 10 years, often lower, then adjusts within caps. Fixed fits long-term owners who want certainty; an ARM can fit buyers likely to move or refinance before it adjusts.
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What is the difference between a fixed-rate mortgage and an ARM?
Fixed rate
The interest rate and principal-and-interest payment never change for the life of the loan. Common terms are 30-year and 15-year.
Adjustable rate (ARM)
A fixed rate for an initial period—often 5, 7, or 10 years—then the rate adjusts periodically based on an index plus a margin, within caps. See ARM loans.
A "5/1" ARM is fixed for five years, then adjusts once a year. Many newer ARMs are written as "5/6" or "7/6," meaning they adjust every six months after the fixed period. Initial ARM rates are often lower than 30-year fixed rates, but not always—the spread changes with the rate environment.
30-year fixed vs. 5-year and 7-year ARMs
| 30-year fixed | 5-year ARM | 7-year ARM | |
|---|---|---|---|
| Initial fixed period | 30 years | 5 years | 7 years |
| Starting rate | Typically highest of the three | Often lowest | Often in between |
| Payment after fixed period | Same | Can rise or fall within caps | Can rise or fall within caps |
| Best fit | Long-term owners who want certainty | Likely moving or refinancing within ~5 years | Likely moving within ~7 years |
How much could an ARM payment go up?
ARMs have caps that limit how much the rate can change. A common structure is "2/1/5": up to 2% at the first adjustment, 1% at each later adjustment, and 5% over the life of the loan (exact caps vary).
Illustrative example: $320,000 loan
Say the ARM starts 0.75% below a comparable fixed rate, saving about $155/mo for five years—roughly $9,300 total. If the rate rises the full 2% at the first adjustment, the payment could rise by about $400/mo. If rates fall, it could go down instead. Illustrative only, not a commitment to lend.
The question to ask: if the payment hit its maximum, could I still afford it? If the answer is no, a fixed rate is likely the better fit.
Who should choose a fixed rate, and who should consider an ARM?
Fixed is usually better if you…
- Plan to stay long-term
- Want a payment that never surprises you
- Have a tight budget with little room for increases
- Don't want to rely on refinancing later
An ARM may fit if you…
- Expect to sell or relocate before the fixed period ends
- Expect income to grow and can handle a higher payment
- Have a larger loan where the initial savings are meaningful
- Understand the caps and have reserves
Common fixed vs. ARM misconceptions
- "I'll just refinance before it adjusts." Maybe—but that depends on future rates, your credit, and your home value. Plan as if you can't.
- "ARMs are what caused 2008." Today's ARMs require qualifying with reasonable payment assumptions and include caps; the risky loans of that era are largely gone.
- "A 15-year is always better." A 15-year fixed saves interest but has a much higher payment. Extra payments on a 30-year can split the difference.
Compare payments in the payment calculator or browse all loan programs.
What should I ask before choosing an ARM?
- What index and margin does it use? The adjusted rate is the index plus the margin, so the margin matters for the life of the loan.
- What are the exact caps? Know the first, periodic, and lifetime caps, and calculate the maximum possible payment.
- How often does it adjust after the fixed period? Every six months and once a year behave differently.
- Is there a prepayment penalty? Most standard ARMs don't have one, but confirm.
- How much am I actually saving? Compare the initial ARM payment to a fixed payment and multiply by the fixed months.
- What's my plan if I'm still here at adjustment? Refinance, sell, or keep the ARM—each should be affordable.
a loan officer can lay a fixed rate and an ARM side by side with the worst-case payment so the decision is clear.
Frequently asked questions
Is a fixed or adjustable-rate mortgage better?
Fixed is better for long-term owners who want certainty. An ARM can save money if you are likely to move or refinance before the fixed period ends and can handle a possible increase.
What does 5/1 ARM mean?
The rate is fixed for 5 years, then adjusts once a year. A 5/6 ARM adjusts every six months after the initial 5 years.
How much can an ARM rate go up?
Caps limit it. A common 2/1/5 structure allows up to 2% at the first adjustment, 1% at each later adjustment, and 5% over the life of the loan.
Are ARM rates always lower than fixed rates?
Usually at the start, but not always. The difference depends on the current rate environment.
Can I switch from an ARM to a fixed rate later?
Yes, by refinancing, if you qualify at that time. It is not guaranteed, so plan for the possibility of keeping the ARM.
Educational answers only—not a loan offer or commitment to lend. Examples are illustrative only, not a commitment to lend.
Compare fixed and ARM side by side
We will show both payments, the worst-case ARM payment, and which fits your plans. Call a loan officer at (480) 233-7897.