Fixed-Rate and Adjustable-Rate Mortgages

Choosing a mortgage means choosing how interest will work over time. The two common options are fixed-rate mortgages and adjustable-rate mortgages, often called ARMs. Both can help someone buy a home, yet they create different payment schedules and different levels of risk.

A mortgage is a loan used to buy property. The lender provides money for the purchase. The borrower repays the amount borrowed, plus interest, through monthly payments that often last 15 or 30 years.

The interest rate matters because it changes the cost of borrowing. A higher rate raises the monthly principal-and-interest payment and increases the total interest paid over the life of the loan. Taxes, homeowners insurance, and homeowners association fees can also change the full housing payment.

A fixed-rate mortgage keeps the same interest rate from the first payment through the last. Someone who takes out a 30-year loan at 6 percent keeps that 6 percent rate for all 30 years. The principal-and-interest payment stays the same, assuming the borrower does not refinance or modify the loan.

That stability helps buyers plan. Property taxes and insurance premiums can rise, so the total monthly payment may still change. The loan’s interest rate and principal-and-interest amount do not change.

Thirty-year fixed mortgages remain common because the long repayment period keeps the monthly payment lower than a shorter loan. The tradeoff comes from interest. Since the borrower takes longer to repay the loan, the total interest cost is usually much higher.

A 15-year fixed mortgage works differently. The homeowner pays off the loan in half the time and often receives a lower interest rate. The monthly payment rises because the lender needs to collect the borrowed money much faster.

Take a buyer borrowing $400,000. A 30-year mortgage may provide a lower monthly payment and leave more room in the budget for savings, repairs, and other expenses. A 15-year loan may cost more each month, yet it can save a large amount of interest over the full repayment period.

An adjustable-rate mortgage begins with a fixed rate for a limited period. After that period ends, the rate can move up or down at scheduled intervals. The loan may be written as a 5/1 ARM, a 7/1 ARM, or a 5/6 ARM.

With a 5/1 ARM, the initial rate stays fixed for five years. The rate can then change once a year. With a 7/1 ARM, it stays fixed for seven years before annual changes can begin. A 5/6 ARM starts with five fixed years, then adjusts every six months.

ARMs often start with a lower rate than a comparable fixed-rate loan. That lower starting rate reduces the payment during the fixed period. In July 2026, the average 5/1 ARM rate was about 6.06 percent. The average 30-year fixed mortgage rate stood near 6.60 percent. On a large loan, even that difference can affect the monthly payment.

An ARM can work for a buyer with a short and realistic time frame. Someone planning to sell in three or four years may prefer a five-year fixed period and a lower starting payment. A buyer relocating for work, attending school, or completing a military assignment may have a reason to expect a move before the rate can adjust.

The risk begins after the fixed period. The ARM rate can increase when its index rises. A homeowner who could afford the original payment may face a much higher one after the first adjustment. That possibility matters even if the borrower plans to sell or refinance before the adjustment date.

An ARM rate usually comes from an index plus a margin. The index moves with broader market interest rates. The margin is a set percentage added by the lender. When the introductory rate ends, the lender uses the current index and the margin to calculate the new rate, subject to the loan’s caps.

Rate caps limit how far an ARM rate can move. The initial adjustment cap limits the first change after the fixed period. The subsequent adjustment cap limits later changes. The lifetime cap limits the total increase or decrease over the loan’s life.

A common cap structure might be 2/2/5. The rate could change by up to 2 percentage points at the first adjustment, by up to 2 percentage points at later adjustments, and by no more than 5 percentage points above the starting rate over the life of the loan. The exact cap structure depends on the mortgage contract.

For example, a borrower could start with a 5 percent ARM that carries a 5 percent lifetime cap. The rate could potentially reach 10 percent. The rate may never rise that far. Buyers should still review the highest possible payment before accepting the loan.

The lender must provide a Loan Estimate within three business days after a mortgage application. The document shows whether the interest rate can change, when changes can begin, how often adjustments can occur, and how high the rate and payment could go. Buyers can compare Loan Estimates from different lenders before choosing a loan.

An ARM can become risky when a buyer uses the lower initial rate to qualify for more home than they could afford at a higher payment. The first payment may fit the budget. A later adjustment could create a serious problem. Buyers should test the budget against the maximum payment permitted by the loan’s caps.

Refinancing can change the loan type later. A homeowner may refinance an ARM into a fixed-rate mortgage if rates fall or if their financial position improves. That plan carries uncertainty. Refinancing requires approval, comes with closing costs, and may not work if rates remain high, income falls, credit weakens, or the home loses value.

A fixed-rate mortgage protects the homeowner from future rate increases. If market rates rise from 6 percent to 8 percent, someone with a fixed 6 percent loan keeps the original rate. That benefit becomes more valuable when the borrower expects to own the home for many years.

An ARM gives the borrower a lower initial rate and the possibility that future adjustments may fall if market rates decline. It also exposes the borrower to the chance of larger payments. The right option depends on how long the buyer expects to keep the loan, how secure their income is, how much savings they have, and whether they could handle a higher payment.

First-time buyers often prefer fixed-rate loans because stable principal-and-interest payments make budgeting easier. A buyer with short-term plans, strong savings, and room for payment increases may consider an ARM after reviewing every adjustment term.

Both loan types can fit the right situation. A fixed-rate mortgage provides a stable interest rate for the full loan term. An ARM can lower costs during its initial fixed period, then introduces the possibility of payment changes. The buyer should compare the full monthly payment, the highest possible payment, closing costs, and their plans for the home before deciding.