Adjustable-Rate Mortgages: How 5/6, 7/6 and 10/6 ARMs Work
An adjustable-rate mortgage can provide a fixed introductory rate for several years before the rate becomes eligible to change. Learn how modern ARMs are structured, what controls future adjustments and how to compare potential savings with long-term risk.
What Is an Adjustable-Rate Mortgage?
An adjustable-rate mortgage, commonly called an ARM, combines an initial fixed-rate period with a later adjustable period. After the fixed period expires, the rate may change according to the loan’s index, margin and adjustment caps.
Initial fixed period
A 5/6 ARM is fixed for five years, a 7/6 ARM for seven years and a 10/6 ARM for ten years.
Adjustment frequency
The “6” means the rate is eligible to change every six months after the fixed period ends.
Rate protections
Initial, periodic and lifetime caps limit potential changes. Exact cap structures vary by loan program.
ARM does not mean the rate changes immediately
A hybrid ARM behaves like a fixed-rate mortgage during its introductory period.
How Does a Modern ARM Work?
Understanding these items helps you estimate the possible payment range before selecting an adjustable-rate loan.
The index
The index is the variable market component. Many conventional ARMs use a SOFR-based index. When the applicable index changes, the fully indexed rate may also change at an eligible adjustment date.
View SOFR informationThe margin
The margin is the fixed percentage added to the index when calculating the fully indexed rate. It is established in the loan agreement and does not change after closing.
Adjustment caps
Caps establish the maximum permitted change at the first adjustment, at later adjustments and over the life of the loan. Do not assume every ARM uses the same cap structure.
Payment recalculation
If the rate changes, principal and interest are generally recalculated using the remaining balance, remaining term and new rate. Taxes, insurance and mortgage insurance are separate.
5/6 vs. 7/6 vs. 10/6 ARM
A longer fixed period provides more initial stability, while a shorter period may offer different pricing. Availability and pricing depend on the lender, investor, property and borrower profile.
5/6 ARM
5 years fixed- Rate fixed for five years
- Eligible to adjust every six months afterward
- May fit a clearly defined shorter ownership horizon
Consider when: Your expected move, sale or payoff is comfortably before the first adjustment.
7/6 ARM
7 years fixed- Rate fixed for seven years
- Eligible to adjust every six months afterward
- More runway than a five-year introductory term
Consider when: You want a meaningful fixed period but may not keep the original loan long term.
10/6 ARM
10 years fixed- Rate fixed for ten years
- Eligible to adjust every six months afterward
- Longest introductory stability of these examples
Consider when: You value a longer planning horizon while retaining an ARM structure.
Example 7/6 ARM Adjustment Timeline
The rate remains fixed through year seven. Beginning after that period, it is eligible to adjust every six months, subject to the index, margin and caps in the loan agreement.
Initial fixed-rate periodScheduled principal-and-interest payments use the same note rate.
Adjustment periodRate may rise, fall or remain unchanged at eligible intervals.
Plan for the maximum—not only the introductory payment. Ask for the first-adjustment, fully indexed and maximum permitted payment.
How Could an Introductory Rate Affect the Payment?
This hypothetical example demonstrates payment mechanics. It is not a current rate quote or a promise that an ARM will be priced below a fixed-rate loan.
30-Year Fixed
6.75%$2,594/mo.Rate and principal-and-interest payment remain fixed for the scheduled term.
7/6 ARM
6.25%$2,463/mo.Rate is fixed for seven years, then eligible to adjust every six months.
Compare total costs, points, APR, caps and expected ownership period—not merely the starting payment.
Example assumes a fully amortizing $400,000 loan over 30 years. Calculations are rounded and exclude property taxes, homeowners insurance, mortgage insurance, association dues and closing costs. Rates are hypothetical and provided only to explain payment mechanics. Actual rates, APRs, points, payments and eligibility vary.
Why Do Some Buyers Choose an ARM?
Potentially lower initial payment
An ARM may be priced differently from a fixed-rate mortgage, reducing the initial payment when the ARM rate is lower.
Matches some shorter timelines
A fixed introductory period can align with buyers expecting to sell, relocate or pay off the loan before adjustments begin.
More options to compare
Reviewing both structures may reveal different combinations of rate, points, payment and closing costs.
When Might a Fixed Rate Be Better?
Long-term ownership
A fixed-rate loan may be easier to plan around when you expect to keep the mortgage beyond the ARM’s introductory period.
Limited payment flexibility
Borrowers with little room for a future payment increase may prefer fixed principal and interest.
Preference for simplicity
A fixed-rate mortgage avoids monitoring an index, adjustment dates, margins and multiple caps.
Who Might Consider an Adjustable-Rate Mortgage?
An ARM should be evaluated against a realistic timeline and conservative future-payment budget.
Relocating professionals
Buyers with a documented assignment or likely relocation before the introductory period expires.
Starter-home buyers
Households expecting the property to meet their needs for a defined period rather than indefinitely.
Early-career professionals
Borrowers anticipating income growth who can still qualify and budget under required ARM calculations.
Military households
Service members whose expected duty-station timeline may align with the initial fixed period.
Borrowers with strong reserves
Buyers who can absorb the maximum payment permitted by the loan’s cap structure.
Strategic comparison shoppers
Borrowers willing to compare worst-case payment and total cost with fixed-rate alternatives.
Ask for these five numbers
- 1The initial interest rate and APR
- 2The index and margin
- 3The initial, periodic and lifetime caps
- 4The payment at the first possible adjustment
- 5The maximum possible payment
Conforming and Jumbo ARM Considerations
The 2026 baseline conforming loan limit for a one-unit property in most U.S. counties is $832,750. A loan above the applicable county limit may require jumbo financing, which can involve different products, reserves, underwriting and pricing.
Loan limits apply to the original loan amount—not the purchase price. Confirm the limit for the property county and number of units.
Review FHFA loan limitsAdjustable-Rate Mortgage FAQs
What does 7/6 ARM mean?
The rate is fixed for seven years and is eligible to adjust every six months afterward.
Can an ARM rate go down?
Yes. At an eligible adjustment date, the rate may increase, decrease or remain unchanged depending on the index, margin, floors, rounding rules and caps.
What is SOFR?
SOFR is the Secured Overnight Financing Rate, a broad measure of overnight borrowing costs collateralized by U.S. Treasury securities. Many conventional ARMs use a published SOFR average as their index.
What is the margin on an ARM?
The margin is a fixed number of percentage points added to the index when determining the fully indexed rate.
What are ARM rate caps?
Caps limit how much the rate may change at the first adjustment, at later adjustments and over the life of the loan.
Is every ARM structured with 2/1/5 caps?
No. Cap structures vary. Review the Loan Estimate, ARM disclosure and note for the exact terms.
Can I refinance before the ARM begins adjusting?
You may apply, but future approval and savings are not guaranteed. Rates, value, credit, income, equity, costs and underwriting will matter.
Is an ARM always cheaper than a fixed-rate mortgage?
No. Compare rate, APR, points, closing costs, caps and expected loan duration for every option.
How is the payment calculated after an adjustment?
The servicer generally applies the new rate to the remaining balance over the remaining term. Escrow changes can affect the total payment separately.
How should I compare an ARM with a fixed-rate loan?
Compare initial payment, APR, points, costs, break-even period, first-adjustment payment, maximum payment and expected loan duration.
Mortgage Rate Resources
Rick Woodruff, NMLS #248984
Rick Woodruff reviews Metropolitan Mortgage educational content for practical guidance relevant to Kansas and Missouri homebuyers. Product availability, pricing and underwriting requirements can change and should be confirmed with a licensed loan officer.
Is an ARM or Fixed-Rate Mortgage Better for Your Plans?
Compare the introductory payment, total closing costs, adjustment caps and maximum potential payment before choosing a structure.