A fixed-rate mortgage locks in the same interest rate for the entire loan term, most commonly 30 or 15 years, meaning your principal and interest payment stays exactly the same every month for the life of the loan. This predictability is the main appeal — buyers know exactly what they're committing to for decades, with no risk of payment shock from rate changes. An adjustable-rate mortgage (ARM) starts with a fixed rate for an initial period — commonly 5, 7, or 10 years — that's typically lower than a comparable fixed-rate loan, then adjusts periodically (often annually) based on a market index, within limits set by caps in the loan terms. This can mean lower initial payments, but it introduces real uncertainty about what payments will look like once the adjustment period begins. ARMs can make sense for specific situations — a buyer who's confident they'll sell or refinance before the fixed period ends, or someone who needs the lower initial payment to qualify and expects their income to grow before adjustments begin. They're riskier for buyers planning to stay in a home long-term, since there's no guarantee rates will be favorable when the adjustment period starts, and payment increases at that point can be significant depending on market conditions. For most buyers planning to stay in a home for the long haul, a fixed-rate mortgage remains the more conservative, predictable choice. The right decision depends on your specific timeline, risk tolerance, and how confident you are in your future plans — a lender can run the numbers on both options against your specific situation to show what the real tradeoff looks like in dollar terms, not just conceptually.