Tool · San Diego specific

What this house actually costs per month

Mortgage, base property tax, Mello-Roos, insurance and HOA in one number — because in Del Sur, 4S Ranch and Torrey Highlands the last three are the difference between a payment you can make and one you can't.

The loan

Purchase price

Down payment

Interest rate

Term

The tax bill

Base property tax rate

Proposition 13 sets the general levy at 1% of assessed value. Voter-approved bonds sit on top, which is why most San Diego parcels land a little above 1%. Your actual rate is on the bill.

Mello-Roos / CFD special tax — the one that gets missed

Per year. This is a fixed charge, not a percentage — it does not scale with what you pay for the house.

I don't know the Mello-Roos. How do I find it?

Two minutes, and it's public. You do not need me for this.

Open the County Treasurer–Tax Collector parcel search.
Search by street address, or by parcel number if you have it from the listing.
Open the current secured tax bill.
Look for Fixed Charge Special Assessments. Community Facilities District entries appear there as their own line items.
Add up the CFD lines and put the annual total in the box.

Add up every line, not just the familiar ones. This is where people go wrong. A city's own list of districts will never show you a special tax levied by a school district — and school district CFDs are exactly where the residential assessments come from in Carmel Valley and much of Carlsbad. The County Auditor publishes a register of every active district in the county, listed by the agency levying it. It is the document to check.

A warning about scenarios. If you're comparing communities rather than a specific house, try $0, then $2,000, then $4,000 and watch what happens to the monthly figure. Those are illustrations of the impact, not the rate for any community — real assessments vary parcel by parcel, even between neighbouring streets in the same development. Never buy on a neighbour's number.

Background: County Assessor on Mello-Roos · City of San Diego CFD information

Everything else

Homeowners insurance

Per year. Get a real quote during your contingency period — in higher fire hazard zones this number has moved a great deal.

HOA dues

Per month. Include any sub-association.

Nothing you type here leaves your device

This calculator runs entirely in your browser. There is no server, no account, no tracking of what you enter, and nothing is sent to me. Close the tab and it's gone. If you want me to look at your actual numbers, that's a phone call — not a form.

Estimated total per month

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Monthly cost breakdown
Principal & interest	—
Base property tax	—
Mello-Roos / CFD	—
Insurance	—
HOA	—
Total	—

What a national calculator would have told you

Assumptions

Assessed value is taken as the purchase price. On a resale in California a sale normally triggers reassessment to market value, so this is usually right in year one.
No mortgage insurance included. Below roughly 20% down, most conventional loans add PMI — ask your lender what it would be.
No impound/escrow account timing, no supplemental tax bill. After a purchase California issues a supplemental bill for the difference between the old assessment and yours — a real one-off cost in your first year that this figure excludes.
Taxes shown at today's rate. Under Proposition 13 the assessed value can rise no more than 2% a year, so this figure grows slowly and predictably.
No utilities, maintenance or reserves.

This is an estimate, not a quote

It is built for planning and comparison, not for closing. Real figures depend on your lender, your parcel, your insurer and your escrow. The single most common error is a Mello-Roos figure taken from a neighbouring property rather than this parcel. Verify against your actual tax bill, your lender's Loan Estimate, and your escrow's settlement statement before you rely on any of it.

Why this tool exists

Every national mortgage calculator assumes a property tax rate of roughly 1.1% and stops there. In most of America that is fine. In the northern I-15 corridor it is wrong by thousands of dollars a year, because Del Sur, 4S Ranch, parts of Torrey Highlands, Santaluz and others sit inside Community Facilities Districts, and a Mello-Roos special tax is a fixed charge that no percentage-based calculator will ever show you.

I have watched buyers get to closing and discover their real payment is several hundred dollars a month above what they had planned for. Not because anyone lied — because the tool they used wasn't built for here.

So: put the real number in, get the real figure out, and decide with your eyes open. Then call me and I'll pull the actual bill on any address you're serious about.