Fixed-Rate vs. Adjustable-Rate Mortgage: Which Should You Choose in 2026?
Short answer: A 5/1 ARM and a 7/1 ARM are the two adjustable loans almost every DMV buyer is actually choosing between. A fixed rate mortgage keeps the same rate for the whole term. An adjustable rate mortgage holds a lower rate for an opening period, usually five, seven or ten years, then resets on a schedule for the rest of the term. The trade is real but it is not the one most people think. The risk is not the index moving, it is the caps, which on a common 2/2/5 structure allow the rate to climb five percentage points above where it started. For the week ending September 10, 2026 Freddie Mac put the 30 year fixed at 6.76 percent and the 15 year at 6.09 percent. There is no equivalent official ARM number, and that matters more than it sounds.
Most articles on this question compare two rates and declare a winner. That is not how the decision actually works, because the two loans are not priced against each other on any day you can look up. What you are really choosing between is certainty and a discount whose size you have to get from a lender and whose ceiling is written into your note. A JB Financing mortgage adviser can put both structures side by side on your actual loan amount, which is the only comparison that means anything.
This guide covers how an adjustable rate is built, what the caps really allow, what the numbers look like on a loan size that is normal in this region, and the federal rule that quietly makes the most aggressive ARMs the hardest ones to qualify for. Every rate, rule and date below is sourced. Where no authoritative figure exists, and for ARM rates today there is none, we say so rather than printing a number.
“Tell me the loan amount and how long you actually plan to keep the house. That second answer decides this, not the rate sheet. I can run the fixed and the adjustable side by side on your file in about ten minutes.”
Arslan Jamil, Broker Associate
Loans originated by Ken Byrne, NMLS ID# 187129 · ALCOVA Mortgage LLC, NMLS ID# 40508. Equal Housing Lender.
ARM vs fixed rate mortgage: what actually changes
A fixed rate mortgage is one number for the life of the loan. Nothing about the rate moves. Your payment can still change as taxes and insurance change, but the principal and interest portion is locked from the first payment to the last. That is the entire product.
An adjustable rate mortgage has two lives. In the first, the rate is fixed at a promotional level for a stated number of years. In the second, it recalculates on a schedule using a formula written into your note. The names describe both halves. A 5/1 is fixed for five years then adjusts once a year. A 7/1 is fixed for seven then adjusts annually. A 5/5 is fixed for five then adjusts only every five years after that, which is a materially gentler structure that very few articles mention. If the monthly difference is what you are weighing, the mortgage calculator will show you the gap on your own numbers.
The part nobody tells you: there is no official ARM rate anymore
Freddie Mac’s Primary Mortgage Market Survey is the benchmark almost every rate headline in the country is built on. It still publishes the 30 year and 15 year fixed every week. It stopped publishing adjustable rates in November 2022, and it has not resumed. Freddie Mac’s stated reason is that ARMs remain most popular on higher loan size, nonconforming loans, while the survey covers conforming products where fixed rate loans dominate.
The practical consequence is that when a site shows you an ARM rate today, it is not coming from a national survey, because none exists. It is a lender average, an advertised rate, or a rate on a specific loan profile you may not match. That is not dishonest, but it is a different kind of number from the 6.76 percent 30 year fixed figure sitting next to it, and the two should not be compared as though they were measured the same way. The only ARM rate that means anything to you is the one a lender will actually write on your file.
How a 5/1 ARM rate is built: index, margin and caps
Once the fixed period ends, your rate is the index plus the margin, limited by the caps. The index is a published market rate that moves on its own. Since the LIBOR Act and the Federal Reserve’s implementing rule, LIBOR was replaced by SOFR based rates after June 30, 2023, so SOFR is the index you will see on a new adjustable rate loan. The margin is a fixed number of percentage points your lender adds on top, and unlike the index it never changes for the life of the loan.
That distinction is worth sitting with. You cannot control the index and neither can your lender. You can compare margins between lenders, and a margin that is half a point higher is half a point higher on every single adjustment for as long as you hold the loan. It is the part of the formula that is negotiable and the part almost nobody asks about.
The caps are the whole risk, so read them in the right order
Caps are the only thing standing between you and the market. The Consumer Financial Protection Bureau describes three, and they do different jobs. The initial adjustment cap limits how far the rate can move the first time it resets, and is commonly 2 percent or 5 percent. The subsequent adjustment cap limits each reset after that, commonly 1 percent or 2 percent. The lifetime cap limits how far the rate can move over the whole loan, most commonly 5 percent.
| Cap | What it limits | Common values | Why it matters |
|---|---|---|---|
| Initial adjustment | The first reset after the fixed period ends | 2% or 5% | A 5 percent initial cap can undo the entire discount in one step |
| Subsequent adjustment | Every reset after the first | 1% or 2% | Decides how fast the rate climbs once it starts moving |
| Lifetime | Total movement over the life of the loan | Most commonly 5% | This is your true worst case, and it is the number to price |
Source: Consumer Financial Protection Bureau guidance on adjustable rate mortgage rate caps. Caps are set in your note and vary by lender and program, so the values above are typical, not universal. Some loans also carry a floor limiting how far the rate can fall.
Read them in that order and one thing becomes obvious. A 5/1 with a 5/2/5 cap structure and a 7/1 with a 2/2/5 structure are not remotely the same product, even though both advertise as an ARM and both cap out five points above the start. The first can get there in a single step. The second needs three. Ask for the cap structure before you ask for the rate.
What this looks like on a loan size that is normal here
Take a $600,000 loan, which is unremarkable across Northern Virginia, Montgomery County and much of the DC market. At the 6.76 percent 30 year fixed rate Freddie Mac reported for the week ending September 10, 2026, principal and interest runs about $3,896 a month. At that size you are inside conventional conforming territory everywhere in the region. Now put an adjustable next to it at three hypothetical discounts.
| Structure | Rate used | Monthly principal and interest | Monthly saving vs fixed | Saved over a five year fixed period |
|---|---|---|---|---|
| 30 year fixed | 6.76% | $3,896 | n/a | n/a |
| ARM, 0.50% lower | 6.26% | $3,698 | $197 | about $11,842 |
| ARM, 0.75% lower | 6.01% | $3,601 | $294 | about $17,665 |
| ARM, 1.00% lower | 5.76% | $3,505 | $390 | about $23,420 |
Illustration only. The 6.76 percent fixed rate is Freddie Mac PMMS for the week ending September 10, 2026. The ARM rates are hypothetical discounts, NOT quoted rates, because no official ARM survey exists. Principal and interest only, $600,000 loan, 30 year amortization. Your rate depends on credit, loan to value, loan amount and lender.
Now the other half of the picture, which almost no comparison article prints. Take the middle row, a 6.01 percent start on a 2/2/5 cap structure, and walk it to its ceiling.
| When | Rate | Monthly principal and interest | Change from the start |
|---|---|---|---|
| Fixed period | 6.01% | $3,601 | n/a |
| First adjustment | 8.01% | $4,407 | up $806 |
| Second adjustment | 10.01% | $5,270 | up $1,669 |
| Lifetime cap reached | 11.01% | $5,718 | up $2,117 |
Illustration only, same $600,000 loan, showing the maximum the note permits under a 2/2/5 cap structure. It assumes every adjustment goes the full allowable amount, which requires the index to move that far. It is a ceiling, not a forecast. Rates can also fall, and some notes carry a floor limiting that.
That is the honest frame. You are trading roughly $294 a month now against a note that permits roughly $2,117 a month more later. Whether that is a good trade depends almost entirely on whether you will still hold the loan when the second column starts. For most buyers the answer turns on the same arithmetic that decides the 15 year versus 30 year question: how long you actually stay.
“The worst case column is the one to look at, not the first one. Send me the note terms you have been offered and I will tell you what the ceiling payment actually is on your loan amount before you sign anything.”
Arslan Jamil, Broker Associate
Loans originated by Ken Byrne, NMLS ID# 187129 · ALCOVA Mortgage LLC, NMLS ID# 40508. Equal Housing Lender.
The five year rule, and why a 7/1 ARM is safer than a 3/1
Federal lending rules contain a detail that reverses most people’s intuition. Under the ability to repay requirements, a qualified mortgage with an adjustable rate has to be underwritten using the maximum interest rate that may apply during the first five years after the first regular payment is due, not the teaser rate. The general ability to repay standard separately requires the greater of the fully indexed rate or the introductory rate.
Follow that through. On a 3/1 ARM the first adjustment lands inside that five year window, and so does the second, so the qualifying rate has to include those increases. On a 7/1 or a 10/1 the first adjustment falls outside the window entirely, so the qualifying calculation starts from a much lower number. The loan that exposes you soonest is the one that is hardest to get approved on, and the one that exposes you latest is the easiest. If your debt to income ratio is tight, this rule will shape which structures are even available to you.
When an adjustable rate is genuinely the better choice
There are real cases, and they share one feature: a specific, credible reason the loan ends before the risk starts. A military family on orders with a known rotation. A physician or attorney whose income is scheduled to roughly double inside five years. A buyer purchasing a known starter home in a market they have already decided to leave. A borrower with a large liquid position who could simply retire the balance if rates moved against them.
What those have in common is that the exit is planned rather than hoped for. "We will probably refinance" is not a plan, because refinancing requires rates to cooperate, your income to hold and your equity to be intact. Those three things fail together far more often than they fail separately, and they tend to fail in exactly the conditions that would make you want to refinance.
When fixed wins, which is most of the time
A fixed rate wins whenever the holding period is uncertain, which describes most buyers honestly assessed. It wins when the monthly difference is small, because a $197 discount is not worth a $2,117 ceiling. It wins when your budget has no slack, because the entire ARM proposition is that you can absorb an increase you cannot currently predict. And it wins when you would lose sleep, which is not a financial argument but is a real one.
There is also a quieter argument. A fixed rate is a hedge you are paid to hold, in the sense that if rates fall you can refinance into the lower rate, and if they rise you keep the one you have. An ARM gives away that asymmetry in exchange for a discount up front. You can still refinance an ARM, but you are relying on it rather than choosing it.
The regional wrinkle that pushes this decision toward fixed
Freddie Mac’s own explanation for dropping the ARM series is the most useful regional fact in this article: adjustable rate loans are most popular on higher loan size, nonconforming loans. That is where the pricing advantage has historically been largest.
The Washington metropolitan area sits at the top conforming tier for 2026, with a one unit ceiling of $1,249,125 against a national baseline of $832,750. A very large share of purchases that would be jumbo almost anywhere else in the country are conforming here. If the ARM discount is concentrated in the jumbo market and you are not in the jumbo market, the argument for taking adjustment risk is thinner than a national article would suggest. Buyers genuinely above that ceiling are in a different conversation, covered in the jumbo loan guide.
What to check before you sign an adjustable rate note
Ask for these in writing, in this order, before rate. The index and the exact margin. The three caps, stated as initial, subsequent and lifetime. The first adjustment date and the adjustment frequency after it. Whether a rate floor exists. Whether there is a prepayment penalty. And the fully indexed rate as of today, meaning what your rate would be if the loan adjusted this month, which is the single most revealing number on the whole disclosure.
If a lender is slow to give you the fully indexed rate, treat that as the answer. Anyone writing the loan can compute it in seconds. Across Virginia and the rest of the region this is the question that separates a lender explaining a product from a lender selling a payment.
Frequently asked questions
What is a 5/1 ARM?
A 5/1 ARM holds a fixed rate for the first five years, then adjusts once every year for the remaining twenty five years of a thirty year term. The first number is the fixed period in years and the second is how often it adjusts afterward.
What is a 7/1 ARM?
A 7/1 ARM is fixed for seven years and then adjusts annually. Because its first adjustment falls outside the five year window federal qualified mortgage rules look at, it is generally easier to qualify for than a 3/1 with the same caps.
What is a 10/1 ARM?
A 10/1 ARM is fixed for ten years and then adjusts annually. It is the most conservative of the common ARM structures and the closest to a fixed rate loan in practice, since most borrowers sell or refinance inside ten years.
What is a 3/1 ARM?
A 3/1 ARM is fixed for three years then adjusts annually. It carries the most exposure of the common structures, and because two adjustments fall inside the first five years, the qualifying calculation has to assume those increases.
What is a 5/5 ARM?
A 5/5 ARM is fixed for five years and then adjusts only once every five years rather than annually. Fewer adjustments over the life of the loan means the rate climbs toward the lifetime cap far more slowly, which makes it a materially gentler product than a 5/1 with the same caps.
What is an advantage of an adjustable rate mortgage?
A lower rate, and therefore a lower payment, during the opening fixed period. On a $600,000 loan a discount of three quarters of a point is roughly $294 a month, or about $17,665 over a five year fixed period. The advantage is real, it is just time limited.
Is an adjustable rate mortgage a good idea?
It is a good idea when you have a specific, credible reason the loan will end before the adjustments begin, and when your budget could absorb the lifetime cap if it does not. It is a poor idea when the exit plan is simply an intention to refinance later.
Are adjustable rate mortgages bad?
No. They are a legitimate product that is badly matched to most buyers. The problem is rarely the loan, it is buyers taking one for the payment without pricing the ceiling written into their own note.
Can you refinance an adjustable rate mortgage?
Yes, the same way you refinance any mortgage, subject to qualifying again on your income, credit and the property value at that time. That is the important caveat: refinancing is not guaranteed, and it is hardest in the conditions that would most make you want it. The honest test for when refinancing works is worth reading before you rely on it as an exit.
What factors directly affect an adjustable rate mortgage?
Four things. The index, which moves with the market and is now SOFR based following the LIBOR transition. The margin, which your lender sets and which never changes. The caps, which limit each move and the total. And the adjustment frequency, which decides how quickly the rate can travel to its ceiling.
“Send me the note terms, not the rate. The index, the margin, the three caps and the first adjustment date tell me in one read whether the discount you are being offered is worth the ceiling you are accepting.”
Arslan Jamil, Broker Associate
Loans originated by Ken Byrne, NMLS ID# 187129 · ALCOVA Mortgage LLC, NMLS ID# 40508. Equal Housing Lender.
This article is general information, not financial or legal advice and not a commitment to lend or an offer of credit. Loan limits, program rules, premium schedules and rates change, and individual eligibility depends on a full review of your credit, income, assets and the property. Every figure here is an illustration, not a quote. Rates cited are Freddie Mac Primary Mortgage Market Survey figures for the week ending September 10, 2026 and change weekly. Adjustable rate figures shown are hypothetical illustrations, not quotes, because no official adjustable rate survey is published. Confirm anything you plan to act on with a licensed mortgage professional.
Categories
Recent Posts
GET MORE INFORMATION
Broker Associate