Adjustable-Rate Mortgages

How an ARM actually works

An ARM starts with a fixed interest rate for an initial period — commonly 5, 7, or 10 years — that's typically lower than a comparable 30-year fixed rate. After that period ends, the rate adjusts periodically (usually once a year) based on a market index plus a set margin, within limits called caps.

Understanding the caps

Every ARM has rate caps that limit how much the rate can move: a cap on the first adjustment, a cap on each adjustment after that, and a lifetime cap on how high the rate can ever go. Those numbers are the real thing to compare when shopping ARMs — not just the starting rate.

Who this fits well

• Buyers who know they'll sell or refinance before the fixed period ends — a starter home, a job that'll relocate you, a planned move-up purchase
• Buyers who want the lowest possible payment during the fixed period, and are comfortable with some rate uncertainty afterward
• Anyone financing a higher-value property where a lower initial rate meaningfully reduces the payment

What to weigh before choosing one

The math only works out if your plans hold. If there's a real chance you'll still own the home once the fixed period ends, run the numbers on both an ARM and a fixed-rate loan before deciding — I'll walk through both with you.