First Home Equity: What You've Built Since Buying

Updated October 2026 · Rudy Flores

Your first home is also your first look at equity. If you bought a few years ago, this page shows what you have built so far, starting from the price you paid and moving it with Zillow's typical values for your San Diego County ZIP code.

Early on, most of each payment goes to interest, so the principal you have paid may look small next to the change in value. That is normal, and the numbers here help you plan your next step with Rudy.

This is an estimate for planning, from Zillow's ZIP-wide typical values applied to your purchase price. It is not an appraisal, a broker price opinion, an offer, a loan offer, or tax or legal advice, and Rudy is a real estate agent, not a lender, appraiser or tax professional.

How the estimate works

1. We look up Zillow's typical value for your kind of home in your ZIP code, both in the month you bought and in the latest month.
2. Your price moves by the same percentage, and the condition you choose gives a low and a high end.
3. For your purchase loan, the balance is figured from your regular fixed-rate payment, starting the month after you moved in.
4. Equity is the middle value minus what you owe; the net also subtracts selling costs, before any taxes.
5. The Prop 13 figure starts at your price and adds each year's State Board of Equalization factor, at most 2%.

Your Prop 13 value and Prop 19

As a newer owner, your taxable value is close to what you paid. Under Prop 13 it can go up 2% a year at most, so if values keep climbing, your tax base grows more slowly than the market.

Proposition 19 matters later in life: once you are 55 or older, your taxable value may follow you to the next California home you buy, if that purchase is within two years of the sale (three times at most). It is good to know it exists.

Good to bookmark for later: the downsizing calculator and property tax for first-time buyers.

Sources and dates

• Zillow Research, Zillow Home Value Index (ZHVI) by ZIP code: all homes, single-family and condo; middle tier, smoothed and seasonally adjusted (data through September 2026, files updated Oct 16, 2026)
• FHFA House Price Index for five-digit ZIP codes (annual, developmental index, not seasonally adjusted; 2000 = 100), used only for purchases before Zillow's series begin. Citation: Bogin, Doerner and Larson, Local House Price Dynamics: New Indices and Stylized Facts, FHFA Working Paper 16-01 (annual, through 2025)
• Freddie Mac Primary Mortgage Market Survey (PMMS): weekly 30-year and 15-year fixed averages; the page uses the mean for your purchase month (monthly means through October 2026; latest weekly 30-year average 7.24% on Oct 29, 2026)
• California State Board of Equalization, Letter To Assessors No. 2026/002: inflation factors for 1976-77 through 2026-27, with Revenue and Taxation Code section 51 and California Constitution article XIII A, section 2(b) (January 13, 2026)
• California State Board of Equalization, Proposition 19 (checked Oct 30, 2026)
• Assumptions, not sourced figures: the condition range (the same rule of thumb as the home value range tool), 6% selling costs, 20% down, regular payments on a fixed-rate loan starting the month after you bought, and the first inflation factor applying on the first January 1 after your purchase

Questions owners ask

More from Rudy

• Take the Home Strategy Quiz
• Request a Home Value
• Compare My Selling Options
• What Could My Home Sell For?
• Seller Net Proceeds Estimator
• Downsizing Calculator
• Keep or Sell Calculator
• Home Sale Tax Exclusion Estimator
• Buy First or Sell First Planner
• Book a 15-minute call