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Adjustable-Rate Mortgage (ARM) Explained: Risks & Rewards

How ARMs work, 5/1 and 7/1 ARM meaning, rate caps, and when an ARM beats a fixed-rate mortgage.

July 9, 20267 min readBy MyWealthForge
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Key Takeaways

  • 1ARM = fixed rate for initial period, then adjusts periodically.
  • 25/1 ARM: fixed 5 years, adjusts every year after.
  • 3Best if you will sell or refinance before the fixed period ends.
  • 4Understand rate caps — lifetime, periodic, and initial.

ARMs offer lower initial rates than 30-year fixed loans — but payment shock after the fixed period catches many borrowers off guard.

Model fixed vs ARM with our mortgage calculator.

How ARM Adjustments Work

Rate = index (SOFR) + margin. Caps limit how much it can jump per period and over the loan life.

A 2/2/5 cap means max 2% per adjustment, 2% first adjustment, 5% lifetime.

When ARM Makes Sense

You plan to move within 5–7 years. You expect rates to fall before adjustment. You can afford payment at the capped maximum.

Otherwise prefer fixed — see mortgage comparison guide.

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