Fixed-rate and adjustable-rate mortgages
Fixed or adjustable — one question decides it.
Fixed-rate versus adjustable-rate is not a product comparison, it is a structure decision that sits inside whichever program you are using. A conventional loan, a VA loan, an FHA loan and a jumbo can all be written either way.
The question that decides it is how long you will keep this specific loan. Not how long you will own the house — how long you will keep the loan, which is a shorter number for most people once you account for refinancing and moving. If that number is comfortably inside an adjustable-rate mortgage’s fixed period, the ARM is worth pricing. If it is not, or if a payment you cannot predict would keep you up at night, take the fixed rate and stop optimizing.
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Fixed vs ARM at a glance
- Fixed-rate terms
- 30, 25, 20, 15 and 10 years
- Common ARM structures
- 5/6, 7/6, 10/6
- Adjustment frequency
- Every six months after the fixed period
- Caps
- Initial, periodic and lifetime, e.g. 5/1/5
- Index
- Typically 30-day average SOFR, plus a margin
- Qualifying
- Underwritten with the ARM’s own rules
Right for you if
- Fixed: anyone staying put, anyone on a fixed income, anyone who wants the decision finished
- Fixed short-term (15 or 20 years): buyers who can carry the payment and want the interest saving
- ARM: a documented plan to sell or refinance inside the fixed period
- ARM: military buyers expecting a PCS move, where the horizon is genuinely known
- ARM: large loan amounts where the initial rate gap is worth real money monthly
Know before you commit
- Plans change; "we will move in five years" is a forecast, not a fact
- The margin, not the index, is the part of an ARM you are negotiating
- Lifetime caps let the rate move a long way — read the worst case, not the first payment
- A 15-year fixed is a commitment to the higher payment in a bad year, not an option to pay more
- Interest-only structures reduce the payment without reducing the balance
How an ARM actually works
A 7/6 ARM is fixed for the first seven years, then adjusts every six months for the remaining twenty-three. The new rate is an index — commonly a 30-day average of SOFR — plus a fixed margin set at closing. The margin never changes. The index does, which is where the movement comes from.
Caps limit the movement. A 5/1/5 structure means the first adjustment cannot move more than five percentage points, each subsequent adjustment no more than one, and the rate can never exceed the start rate by more than five over the life of the loan. Read those three numbers before you read the initial rate, because they define your worst case.
The comparison that matters
| Fixed-rate | Adjustable-rate | |
|---|---|---|
| Payment predictability | Complete, for the full term | Fixed for the initial period, then variable |
| Initial rate | Usually higher | Usually lower |
| Best when | You are staying, or you want certainty | You are leaving or refinancing inside the fixed period |
| Worst case | You keep paying a rate the market has left behind | Rate rises to the lifetime cap |
| Exit | Refinance when rates fall | Refinance or sell before the first adjustment |
Structural comparison, not a rate quote. The right structure depends on your horizon and your tolerance for a payment that can move.
The shorter fixed terms nobody is offered
Most buyers are quoted a 30-year fixed and nothing else. A 20-year or 25-year fixed frequently prices slightly better than the 30 and cuts total interest substantially, and a 15-year cuts it dramatically. The payment is higher — that is the trade, and for a household with a tight budget it is the wrong trade. But it should be a decision you made rather than a default you were handed. Ask me for all of them.
When an ARM is genuinely the right answer
When the horizon is documented rather than hoped for. A physician finishing a fellowship in four years. An officer with orders. Someone buying a bridge property while a build finishes. In those cases the fixed period covers the whole holding period and the lower initial rate is simply cheaper money. Outside those cases, an ARM taken to afford a house you could not otherwise afford is how people get hurt.
In their words
Clients who used fixed vs arm
#1 Choie for any Mortgage first time buy, refi, and Cash out Refi. Great customer service, responds to every call and text, knowledgeable and experienced, Excellent at communication before performing task to his clients. Answers any questions in a perfessional manner.
Travis and his team are just absolutely wonderful. We just closed on our new house and he was with us every step of the way. This is the 4th time we have used him as our lender over the years and he never disappoints. He is consistent with his knowledge but does it in a way that you feel like you are old friends with him. I tell everyone I know looking to buy a home to call him. I honestly know they will get the same amazing care my husband and I receive by working with him. Can’t say enough good things about him…. If you are looking to buy I highly suggest you reach out to him and his team!
Questions
Fixed vs ARM, answered
It is the predictable choice, which is usually what people mean. It is not always the cheapest — a 20- or 25-year fixed often prices similarly and saves a great deal of interest, and an ARM can be cheaper still if your horizon genuinely fits inside its fixed period.
Fixed for seven years, then adjusting every six months. The older 7/1 naming adjusted annually; the 6 reflects the six-month adjustment period used with SOFR-indexed loans.
As high as the caps allow. A 5/1/5 cap structure means the first adjustment is limited to five percentage points, each later one to one point, and the lifetime increase to five points over the start rate. Ask for the maximum payment at the lifetime cap in writing before you sign.
Usually, and that is often the plan. The risk is that refinancing depends on your credit, your income and the market at that future moment — none of which you control. Build the plan so that keeping the loan is survivable, not just refinancing it.
More in the full mortgage FAQ, or ask me directly.
This is not an offer to enter into an agreement or a commitment to lend. Not all applicants will qualify. Information and rates are subject to change without notice. All loans are subject to credit review and approval. Program guidelines, fees and loan limits are set by the applicable agency or investor and are subject to change. Fairway Home Mortgage is a division of Fairway Independent Mortgage Corporation. NMLS Entity ID #2289.
Next step
Find out what you qualify for before you shop.
A documented pre-approval takes about 24 hours once your paperwork is in, costs nothing, and tells you whether fixed vs arm is genuinely your best route.