Variable Rate Mortgage
A variable rate mortgage, also called an ARM, has interest rates that fluctuate. Understand caps, indexes, and budgeting for rate changes.
Definition
A variable rate mortgage, also known as an adjustable‑rate mortgage (ARM), features an interest rate that changes periodically based on a benchmark index plus a margin. After an initial fixed-rate period, the rate may reset annually or semiannually. Caps limit how much the rate can rise per adjustment and over the life of the loan. Borrowers benefit from lower introductory rates but face uncertainty about future payments. Variable rate mortgages suit borrowers planning to sell or refinance before rate adjustments or who expect rates to decline.
Why It Matters
The number that matters is not the teaser rate, it is the ceiling. A 5/6 ARM starting at 5.75 percent with 2/1/5 caps can legally reach 10.75 percent, and on a $500,000 balance that is roughly $1,700 more per month than where you started. If the plan for the reset is to refinance, note that refinancing depends on rates, your income and your home value at that future date, none of which you control.
Examples
A 7/1 ARM written in 2021 at 2.9 percent adjusts in 2028 to index plus a 2.75 margin, and the payment on a $480,000 loan climbs from about $2,000 to about $3,070.
A buyer expecting a three year assignment abroad takes a 5/6 ARM priced 0.9 points under the 30 year fixed, saves roughly $260 a month, and sells in year four.
A borrower reads the note and finds a 2 percent cap on the first adjustment, 1 percent on each one after, and 5 percent over the life of the loan above a 6.25 percent start rate.
Tips
Have the lender quote the fully indexed rate as of today, meaning current index plus margin, not the introductory rate; if that payment does not fit your budget now, the loan is a bet rather than a plan.
Write down the first adjustment date and the lookback date, then set a reminder eight months earlier so you can refinance or sell on your own schedule rather than the note's.
Ask whether the loan carries a conversion option to fixed, what it costs and what window it is available in, since some ARMs include one and borrowers forget it exists.
Related Terms
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