A fixed-rate mortgage locks in the same interest rate for the entire term. An adjustable-rate mortgage (ARM) starts with a lower rate for a set period, then resets periodically based on market conditions. Both are completely reasonable choices — the right one depends on how long you expect to keep the loan and how much rate uncertainty you can tolerate.
Why ARMs start cheaper
Lenders can offer a lower initial rate because the risk of future rate increases is shifted to the borrower rather than locked in for decades on the lender's books. A common structure quotes a fixed rate for an initial period — 5, 7, or 10 years — before adjusting, usually annually, based on a reference rate plus a margin.
Who tends to benefit from each
A fixed rate suits anyone planning to stay in the home for the long haul, or anyone who simply values knowing the payment will never change — genuine peace of mind has real value. An ARM can make sense if you're confident you'll sell or refinance before the fixed period ends, since you capture the lower initial rate without ever experiencing an adjustment.
The risk with an ARM is that plans change — a move falls through, refinancing options dry up, or rates rise sharply right as your fixed period ends, all at once. Ask what the payment would look like at the maximum allowed rate, not just the starting rate, before deciding you can live with that scenario.
How to compare them honestly
Run the fixed-rate payment through our mortgage calculator, then separately calculate what the ARM's payment would become at its worst-case rate cap. If that worst case still fits your budget comfortably, the lower initial ARM rate may be worth the flexibility. If the worst case would strain your finances, the certainty of a fixed rate is worth more than the initial savings.