ARM vs. Fixed-Rate Mortgage in California: Which Is 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. I’m known as a creative mortgage broker: when a bank says no, I find the lender and the loan structure that can say yes. I model the fixed and ARM options side by side — including the worst case — before any client decides. Call (800) 239-1103.

An adjustable-rate mortgage (ARM) usually starts below a 30-year fixed rate, then can change after an initial fixed period of 5, 7, or 10 years. It fits borrowers with a realistic plan to sell or refinance before the first adjustment and the ability to handle the worst-case payment. A fixed rate fits anyone who wants a payment that never changes or expects to stay long term.

Fixed vs. Adjustable: The Basics

A fixed-rate mortgage keeps the same interest rate for the whole term — commonly 30, 20, 15, or 10 years. Your principal-and-interest payment never changes.

An ARM has a fixed rate for an initial period, then resets on a schedule to an index plus a margin, limited by caps:

• Index: most new ARMs use SOFR; Fannie Mae and Freddie Mac require the 30-day average SOFR published by the Federal Reserve Bank of New York. (LIBOR is gone.)
• Margin: a fixed number of percentage points set at closing and added to the index. Freddie Mac allows margins from 1% to 3% on its SOFR ARMs.
• Caps: limits on how far the rate can move at the first adjustment, at each later adjustment, and over the life of the loan. Many ARMs also have a floor, often equal to the margin.

What “5/6,” “7/1,” and “2/1/5” mean

The first number is the fixed period in years. The second is how often the rate adjusts afterward. Conforming (Fannie Mae / Freddie Mac) ARMs today are mostly 5/6, 7/6, and 10/6 — fixed for 5, 7, or 10 years, then adjusting every six months. Many jumbo and portfolio lenders still offer 5/1, 7/1, and 10/1 ARMs that adjust once a year.

Cap structures are written as three numbers. A 2/1/5 cap (common on conforming 5/6 ARMs) means up to 2% at the first adjustment, 1% at each later adjustment, and 5% over the life of the loan. A 5/1/5 cap (common on 7/6 and 10/6 ARMs) allows the full 5% at the first adjustment. Jumbo ARMs vary — 2/2/5 and 5/2/5 are common. Your note spells out the exact terms; read them before you lock.

What an ARM Can Save — Illustration

Suppose a $800,000 loan with a 30-year fixed at 7.00% and a 7-year ARM at 6.50%. Spreads between ARMs and fixed rates change constantly — sometimes they’re wide, sometimes barely there — so treat this as an example, not a quote.

	30-Year Fixed at 7.00%	7-Year ARM at 6.50%
Initial principal & interest	$5,322	$5,057
Monthly difference	—	about $266 lower
Savings over the 84-month fixed period	—	about $22,300 in payments
Balance after 7 years	about $729,200	about $723,300

On larger jumbo balances the dollars scale up: every 0.50% on a $2 million loan is roughly $10,000 a year in interest early in the loan.

The Stress Test: Worst Case at Adjustment

Before anyone takes an ARM, I calculate the payment if the rate goes to its cap. Using the example above with a 5/1/5 cap, the rate could reach 11.50% at the first adjustment in month 85. On the remaining balance of about $723,300, that’s a principal-and-interest payment of roughly $7,470 a month — about $2,400 more than the starting payment.

That’s unlikely, but it’s possible. If you couldn’t carry that payment for at least a while — long enough to sell or refinance — an ARM is the wrong tool. Payments can also fall if the index drops, but not below the floor.

When an ARM Makes Sense

• A defined time horizon. You expect to sell, relocate, or move up within the fixed period — for example, a starter condo, a job with a likely transfer, or a home you’ll outgrow.
• Large loan balances. In Marin, San Francisco, and other high-cost areas, jumbo borrowers often see the biggest dollar savings. Some jumbo lenders price ARMs noticeably better than fixed loans.
• Strong income and reserves. High earners who could absorb a higher payment if plans change.
• Second homes and investment properties with a planned sale date, including DSCR loans where near-term cash flow matters most.

When a Fixed Rate Is Better

• You expect to stay 10 years or longer, or you’re buying your “forever” home.
• You’re at the top of your budget and couldn’t handle a payment increase.
• Your only exit plan is “rates will drop and I’ll refinance.”
• Payment uncertainty would cost you sleep. That’s a legitimate reason.

ARMs and Qualifying

A lower start rate doesn’t always mean a bigger approval. For conforming ARMs with an initial fixed period of five years or less, Fannie Mae requires lenders to qualify you at a higher rate than the start rate. Seven- and 10-year ARMs generally qualify at the note rate, so they can help debt-to-income ratios more. Jumbo and non-QM lenders set their own rules.

The “Refinance Later” Plan — and Its Risk

Many borrowers plan to refinance into a fixed rate before the first adjustment. That works if rates are lower, your income still qualifies, and the home holds its value. The risk is that rates are higher, or your situation has changed, right when you need to refinance. Plan to start looking 6–12 months before the first adjustment, not in the final month.

Conventional, FHA, and VA ARMs don’t carry prepayment penalties. Some non-QM and investor loans do, so check before you sign.

How I Help You Decide

As a broker, I can price fixed loans, conforming ARMs, and jumbo ARMs across many wholesale lenders on the same day. For each option I show you the starting payment, the savings over your realistic time horizon, the balance when the fixed period ends, and the worst-case payment. Then you choose with the numbers in front of you.

Frequently Asked Questions

Is an ARM a good idea in California right now?

It can be for buyers who expect to sell or refinance within the fixed period and could handle the worst-case payment. The size of the benefit depends on the spread between ARM and fixed rates on the day you lock, which changes constantly. For long-term owners who want certainty, a fixed rate is usually the better fit.

What does 5/6 or 7/1 mean?

The first number is the number of years the rate is fixed. The second is how often it adjusts afterward: “6” means every six months and “1” means once a year. Most conforming ARMs today are 5/6, 7/6, or 10/6; many jumbo lenders still offer 5/1, 7/1, and 10/1.

How high can my ARM rate go?

The caps in your note set the limit. With a 5/1/5 cap and a 6.50% start rate, the rate can never exceed 11.50%; with a 2/1/5 cap, the first adjustment is limited to 2%. Calculate the payment at the maximum rate on your expected balance before choosing an ARM.

What index do ARMs use now?

Most new ARMs use SOFR. Fannie Mae and Freddie Mac require the 30-day average SOFR published by the Federal Reserve Bank of New York. Your new rate at each adjustment equals the index plus your margin, subject to the caps.

Can I refinance out of an ARM before it adjusts?

Yes. Conventional, FHA, and VA ARMs don’t have prepayment penalties, so you can refinance any time. The risk is that rates or your finances may not cooperate when you need to, so start planning 6 to 12 months before the first adjustment.

Related Resources

• 15-Year vs. 30-Year Mortgage
• Jumbo Loans in California
• California Mortgage Rates
• Why Mortgage Rates Change Daily
• Rate Buydowns in California
• Refinancing in California
• DSCR Loans in California

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