MORTGAGE CALCULATOR

Principal & Interest (P&I)

This is the core of your mortgage payment. Principal is the portion that reduces your loan balance; interest is the cost of borrowing. Your rate, loan amount, and term determine this figure — it remains fixed for the life of a fixed-rate loan.

Property Tax

California property taxes are assessed by the county at approximately 1% of the purchase price, plus any voter-approved local assessments. In San Diego County, the effective rate typically falls between 1.1% and 1.3% depending on the city and any special districts. The calculator defaults to 1.14% — adjust it to match your target area.

What is Proposition 13?

Passed by California voters in 1978, Proposition 13 is a foundational law that shapes how property taxes work in this state. It limits property taxes to 1% of a home's assessed value, plus any local voter-approved assessments. The assessed value is set at the purchase price when you buy — and from that point forward, it can only increase by a maximum of 2% per year, regardless of how much the home appreciates in the market.

This is why long-time homeowners in California often pay significantly lower property taxes than buyers who purchase today at current market prices. When a property sells, the assessed value resets to the new purchase price. As a buyer, your property tax obligation will be based on what you pay — not what the prior owner paid years ago. This is an important distinction to understand when budgeting for a home purchase in San Diego.

What Are Supplemental Property Taxes?

When you purchase a home in California, you will receive a supplemental property tax bill in addition to your regular annual tax bill. This is a one-time charge that covers the difference between the previous owner's assessed value and your new purchase price — prorated for the remaining months of the current fiscal tax year, which runs July 1 through June 30.

Depending on when you close escrow, you may receive one or two supplemental bills. These are billed separately and are typically not included in your lender's initial escrow estimate, so it is important to budget for them on top of your regular property tax payments. Supplemental bills are mailed directly to you by the San Diego County Treasurer-Tax Collector. For full details on how supplemental taxes are calculated and when to expect your bill, visit the San Diego Treasurer-Tax Collector's supplemental tax page.

What Is the Difference Between Assessed Value and Market Value?

These two figures often get confused, but they serve very different purposes. Market value is what a buyer is willing to pay for a home and what a seller can reasonably expect to receive — it is driven by current supply and demand, comparable sales, location, condition, and timing. It fluctuates with the market and is what determines your purchase price.

Assessed value, on the other hand, is the figure the county uses specifically to calculate your property tax bill. In California, thanks to Proposition 13, your assessed value is set at your purchase price when you buy and can increase by no more than 2% per year — even if your home's market value climbs 20% in a single year. Over time, this means a home's market value can far exceed its assessed value, particularly for long-term owners.

As a buyer, your assessed value will start close to your purchase price, so your property taxes will initially reflect current market conditions. But as the years pass, your assessed value grows slowly while your home's market value may rise much faster — which is one of the built-in financial benefits of owning property in California.

Homeowners Insurance

Most lenders require homeowners insurance, and your lender will typically include it in your monthly payment via an escrow account. Costs vary based on coverage, home size, and location — $100 to $250/month is a common range for San Diego County homes.

HOA Dues

Many communities in San Diego — particularly in master-planned developments like Pacific Highlands Ranch, Rancho Tesoro, and Carmel Valley — have Homeowners Associations (HOAs) that charge monthly dues. These cover shared amenities, common area maintenance, and community services. HOA dues vary widely by community; contact us for current rates in a specific neighborhood.

What is Mello-Roos?

Mello-Roos is a special tax assessed in certain California communities to fund infrastructure improvements — roads, schools, parks, and utilities — in newer developments. It is charged in addition to standard property tax and can range from a few hundred to several thousand dollars per year depending on the district. Many newer communities in North San Diego County carry Mello-Roos assessments. We can help you understand the full tax picture for any home you're considering. Read our full Mello-Roos guide →