A 5/6 ARM has a fixed interest rate for five years and can reset every six months afterward under its index, margin, and caps.
A 5/6 hybrid adjustable-rate mortgage (5/6 ARM) has a fixed interest rate for the first five years and can adjust every six months afterward. The applicable reset rate depends on the index, margin, caps, floor, rounding, and timing rules in the mortgage note.
The 5 means a five-year initial fixed-rate period. The 6 means six months between later rate adjustments. It does not mean six adjustments per year or a five-year loan term.
The loan begins like a fixed-rate mortgage and later becomes adjustable:
| Period | Rate behavior | Payment analysis |
|---|---|---|
| Months 1 through 60 | Note rate remains fixed | Principal and interest are generally level under standard amortization |
| After month 60 | Rate can reset every six months | Payment is recalculated from balance, rate, and remaining term |
The uncapped fully indexed rate generally follows:
The applied rate may differ because the contract limits a specific adjustment, imposes a floor, or uses a stated rounding method.
Assume a $300,000, 30-year 5/6 ARM with a 5.50% initial rate. The scheduled monthly principal-and-interest payment for the first five years is approximately $1,703.37.
After 60 scheduled payments, the balance is approximately $277,381.81. Suppose the first reset produces an applied rate of 6.25%. Amortized over the remaining 25 years, the new principal-and-interest payment is approximately $1,829.80.
Six months later, after six scheduled payments, the balance would be approximately $275,040.88. If the next applied rate is 7.00%, the payment for the remaining 294 months would be approximately $1,958.65.
| Point in time | Applied rate | Approximate balance | Remaining months | Monthly principal and interest |
|---|---|---|---|---|
| Origination | 5.50% | $300,000.00 | 360 | $1,703.37 |
| First reset | 6.25% | $277,381.81 | 300 | $1,829.80 |
| Second reset | 7.00% | $275,040.88 | 294 | $1,958.65 |
From the initial period to the second illustrated reset, principal and interest rise by about $255.28 per month. The example excludes taxes, insurance, mortgage insurance, fees, escrow changes, and contract-specific timing or rounding.
A 5/6 ARM can respond to benchmark changes twice as often as a 5/1 ARM after the fixed period. This has effects in both directions:
Frequency alone does not establish which loan costs less. The index, margin, starting rate, caps, fees, and loan term can dominate the comparison.
| Feature | 5/6 ARM | 5/1 ARM |
|---|---|---|
| Initial fixed period | Five years | Five years |
| Later adjustment interval | Every six months | Once each year |
| Potential rate changes after year five | Up to two per year | Up to one per year |
| Response to index movement | Potentially faster | Potentially slower |
| Documents to compare | Index, margin, semiannual cap, lifetime cap, timing | Index, margin, annual cap, lifetime cap, timing |
The second part of an ARM label is not expressed consistently across every product convention. Confirm the plain-language adjustment interval in the note and disclosures rather than relying only on the slash notation.
The first post-fixed payment is not the endpoint. A second reset can occur six months later, so a one-reset affordability test is incomplete.
A plan to exit before month 61 depends on future credit, income, equity, rates, underwriting, closing costs, and loan availability. Those conditions are not guaranteed.
The first adjustment cap may differ from the cap applied every six months afterward. A lifetime cap limits the rate under the note, not all parts of the housing payment.
The index determination date can precede the rate-effective and payment-effective dates. Current market rates may therefore differ from the benchmark value used in the reset.
A falling benchmark does not ensure an immediate or equal payment decrease. Floors, prior capped changes, timing, and rounding can affect the result.
For an existing loan, use the executed note, adjustment notices, payment history, and servicer calculation records. A current benchmark quote alone is insufficient to reproduce a past reset.
This article provides general financial education, not individualized mortgage, refinancing, legal, tax, accounting, or housing advice. The executed note, disclosures, and applicable law govern a specific loan.