Choosing between a fixed-rate mortgage (FRM) and an adjustable-rate mortgage (ARM) is one of the most consequential decisions in the home-buying process — and one I help clients think through regularly. The wrong choice can cost you tens of thousands of dollars over the life of your loan. The right choice depends on how long you plan to stay in the home, your risk tolerance, and the current interest rate environment.
Fixed-Rate Mortgage (FRM): Stability and Simplicity
A fixed-rate mortgage locks in your interest rate for the entire life of the loan — typically 15 or 30 years. Your principal and interest payment never changes, making it easy to budget and plan long-term. This is the option I recommend most often for clients who value certainty and plan to stay in their home.
- Best for: Buyers who plan to stay in the home long-term, those who value payment certainty, and anyone buying when rates are relatively low.
- The trade-off: Fixed rates are typically slightly higher than the initial rate on an ARM, because the lender is absorbing the risk of future rate increases.
Adjustable-Rate Mortgage (ARM): Lower Start, Variable Future
An ARM starts with a fixed interest rate for an initial period (commonly 5, 7, or 10 years), then adjusts periodically based on a market index. For example, a 7/1 ARM has a fixed rate for 7 years, then adjusts annually.
- Best for: Buyers who are confident they’ll sell or refinance before the adjustment period begins, or those buying in a high-rate environment where rates are likely to fall.
- The trade-off: Once the adjustment period begins, your rate — and payment — can rise significantly. I always make sure clients understand this risk before choosing an ARM.
Key Questions I Walk Clients Through
- How long will you stay in the home? If you plan to move within 5–7 years, an ARM’s lower initial rate may make sense. If you’re buying your forever home, a fixed rate is almost always the better choice.
- Where are interest rates today? In a high-rate environment, ARMs offer larger initial savings. In a low-rate environment, locking in a fixed rate is usually the smarter long-term move.
- Can you absorb payment increases? I only recommend an ARM for clients who have the financial cushion to handle their payment rising by hundreds of dollars per month after the adjustment period.
A Note on 15-Year vs. 30-Year Fixed
If you choose a fixed-rate mortgage, you’ll still need to decide on the term. A 15-year mortgage has a higher monthly payment but significantly lower total interest — often half the interest of a 30-year loan. A 30-year mortgage offers lower monthly payments and more cash-flow flexibility, but costs more over time. I help clients model both so they can see the real difference.
Compare Your Mortgage Options