Fixed-Rate vs ARM Mortgage: Which Is Right for You?
An ARM's lower initial rate is genuinely attractive — typically 0.5–1% below a 30-year fixed. But the question is whether you'll actually benefit from it, or if rising rates after the fixed period will cost you more than you saved. The right answer depends almost entirely on how long you plan to stay in the home. Use the calculator to model both scenarios.
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How long do I need to stay for a fixed rate to be worth it?
The break-even point is typically 7–10 years. If you stay less than 5 years, the ARM almost certainly wins. Between 5–10 years it depends on how much rates rise. Beyond 10 years, the fixed rate wins in most scenarios because the ARM's cumulative adjustments tend to exceed the initial savings.
What is the worst-case scenario with a 5/1 ARM?
With a typical 2/2/5 cap structure, your rate can go up 2% at the first adjustment (year 6), then 2% per year after that, up to a maximum of 5% above the initial rate. So a 6.5% ARM could theoretically hit 11.5% — though market conditions would need to be extreme for rates to reach that level.
Are ARMs popular when fixed rates are high?
Yes — ARM market share tends to rise when fixed rates are high, as buyers look for ways to lower their initial payment. In 2023–2024, ARMs became more popular as 30-year fixed rates climbed above 7%. The theory is that buyers can refinance to a fixed rate when rates eventually fall.
Is refinancing from ARM to fixed always possible?
Not guaranteed. You'll need to qualify at the time of refinancing — meeting income, credit, and equity requirements. If home values fall and your equity shrinks, or if your credit situation changes, refinancing may not be available. This is why ARM borrowers should have a solid plan B.
What index do ARMs adjust to?
Most modern ARMs adjust to SOFR (Secured Overnight Financing Rate), which replaced LIBOR as the primary benchmark. Your new rate = SOFR + your loan's margin (typically 2.5–3%). The margin is set at origination and doesn't change — only the index moves.