The choice between an adjustable-rate mortgage (ARM) and a fixed-rate mortgage is one of the most consequential decisions in home financing. Neither is universally better — it depends entirely on your situation.
How Fixed-Rate Mortgages Work
Your interest rate is locked for the life of the loan. Whether rates rise or fall, your principal and interest payment never changes.
Advantages:
- Predictability and stability
- Protection against rising rates
- Easier to budget
Disadvantages:
- Higher initial rate than ARMs
- No benefit if rates fall (you’d have to refinance)
How Adjustable-Rate Mortgages Work
ARMs typically have a fixed initial period (3, 5, 7, or 10 years), then adjust annually based on a benchmark index plus a margin.
A 5/1 ARM is fixed for 5 years, then adjusts every 1 year.
Advantages:
- Lower initial rate (often 0.5–1.5% below 30-year fixed)
- Makes sense if you’ll sell or refinance before the adjustment period
Disadvantages:
- Rate uncertainty after initial period
- Payment can increase significantly
- Caps limit how much it can rise each year and overall, but it can still jump
ARM Caps Explained
Most ARMs have three caps: initial adjustment cap, periodic adjustment cap, and lifetime cap.
A “2/2/5” cap structure means:
- First adjustment: maximum 2% increase
- Each subsequent adjustment: maximum 2% increase
- Lifetime: maximum 5% increase above initial rate
When an ARM Makes Sense
- You’re confident you’ll sell within the fixed period
- You’re in a high-rate environment (expecting rates to fall)
- You want to qualify for a larger loan
- You plan to refinance
We can model the payment scenarios for both options and show you the exact savings and risks based on your purchase price, term, and timeline.