5/1 ARM Loan California: Is a 5-Year Adjustable Rate Right for You?

I’m Michael DiVita — DRE #01372066 | NMLS #241655, DiVita Home Finance (DRE #01818285 | NMLS #323700), Tiburon, CA. I’ve been in California mortgage lending since 2000 and founded DiVita Home Finance in 2007. ARM vs. fixed is one of the most consequential decisions California borrowers make — I model both scenarios with your actual numbers before you decide. Call (800) 239-1103.

A 5/1 ARM locks your rate for the first five years, then adjusts annually. In California’s high-loan-balance market, the savings during the fixed period can be meaningful — though the spread between ARM and fixed-rate loans has tightened considerably in 2026. Here’s who benefits and who should stay fixed.

How the 5/1 ARM Works

Fixed rate for years 1–5. Starting year 6, it adjusts annually based on the SOFR index plus a lender margin (typically 2.5%–3%). Most California 5/1 ARMs carry a 5/1/5 cap structure: maximum 5% up at the first adjustment, 1% per year after that, and 5% maximum increase over the life of the loan. The caps are your protection against runaway rate increases — but they’re not a ceiling on what could happen at year 6 if you’ve held the loan that long. Always run the worst-case scenario before choosing an ARM.

Payment Comparison — 2026 Rates

On an $800,000 California loan: a 30-year fixed at approximately 6.66% produces a principal and interest payment of roughly $5,141/month. A 5/1 ARM at approximately 6.22% produces roughly $4,910/month. Monthly savings of $231, totaling about $13,860 over the five-year fixed period. The spread between the ARM and 30-year fixed is currently about 0.44% — narrower than the historical norm of 0.75%–1.25%. Savings are real but more modest than in prior cycles. Factor that into your decision.

Worst-Case Scenario at First Adjustment

A 5/1 ARM at 6.22% with 5/1/5 caps: at year 6, the rate could jump to 11.22% — producing a payment of roughly $7,720/month on an $800,000 balance. This is the stress test every ARM borrower should run before signing. If you cannot absorb that payment — even temporarily, even with a plan to refinance first — the ARM is the wrong product. I run this scenario for every ARM client before we proceed.

Who the 5/1 ARM Makes Sense For

Tech workers and professionals who typically relocate every 5–7 years — a common profile across Marin, San Francisco, and the Bay Area — are natural ARM candidates if the move is genuinely planned. Buyers in appreciating markets who plan to upsize or sell before year 6 also benefit. Those with a concrete refinance plan before the first adjustment (monitoring rates and ready to lock), and high-income borrowers who can absorb payment variability if circumstances change, are the borrowers for whom the ARM risk-reward calculation tilts positive. The ARM is a bad choice for buyers who intend to hold the property long-term and cannot absorb worst-case payment increases.

Converting to a Fixed Rate

Most California borrowers who take a 5/1 ARM refinance into a fixed rate 12–18 months before the first adjustment kicks in. There is no prepayment penalty on residential ARM mortgages. If you buy now and rates decline over the next few years, you refinance into a lower fixed rate and come out ahead on both ends. If rates stay flat or rise, you’re in a more vulnerable position at year 5 — which is why your exit plan matters before you take the ARM, not after.