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Home Buying Calculator

See the whole monthly cost of a California home, not just the mortgage, plus the cash you'd need at closing and how the payment compares with common lender guidelines. Nothing you type leaves this page.

In one minute

  • Your monthly cost is usually more than principal and interest: add property tax, insurance and sometimes mortgage insurance and HOA dues.
  • In California, the base property tax rate is 1% of assessed value, plus local voter-approved charges.1
  • With less than 20% down, most conventional loans require private mortgage insurance (PMI).2
  • Lenders look at your debt-to-income ratio: monthly debts divided by gross monthly income.3
Calculator

Your numbers

$
%
%
An example. Use the rate from your lender's quote.
%/yr
1% base plus local charges. Check the county tax rate for the address.
$/yr
An example. Get a quote; wildfire areas can cost much more.
$/mo
%/yr
An example. Your lender sets the actual rate.
$/yr
$
Car loans, student loans, credit card minimums.
% of price
A rough planning figure. Your Loan Estimate will list the actual costs.
$0Estimated total monthly housing cost
    $0Cash to close: down payment plus estimated closing costs
    0%Housing cost as a share of gross income. A common guideline is 28% or less
    0%All debts as a share of gross income. Guidelines often use 36%, and 43% is a common upper limit3
    $0Rough price that fits both guidelines with these inputs
    Part 2

    Reading the results

    The 28% and 36% figures are long-standing rules of thumb, not approval rules. Lenders look at your credit, savings, loan type and full debt picture.3 Being "approved" for a payment also doesn't mean it fits your plans for childcare, retirement saving and an emergency fund.

    Green means within the common guideline, gold means above it, and red means above 43%, a level many lenders treat as an upper limit. These are guides, not verdicts.
    Part 3

    Costs people forget

    • Supplemental property tax bill: after you buy, the county reassesses the home and may send an extra bill for the change in value.1
    • Mello-Roos and special assessments: common in newer Southern California developments and added to the tax bill.
    • Maintenance: many owners set aside money every year for repairs and replacements.
    • Earthquake and flood insurance: usually not included in a standard homeowners policy.
    • Life and disability insurance: a mortgage is a reason to check that your family could keep the house if your income stopped. See Planning for a Young Family.

    The mortgage interest deduction applies to interest on up to $750,000 of home loan debt for most newer mortgages, and only if you itemize.4

    Buying a home is a planning decision, not just a payment.

    A conversation can show how a home purchase fits with your savings, insurance and other goals, before you talk with a lender.

    Book a time with Kevin Educational estimates only, not a loan offer or pre-approval. Rates, taxes, insurance and qualification come from your lender, county and insurer.

    Sources

    1. California State Board of Equalization, Publication 800-10 (Proposition 13 and the 1% rate) and Supplemental Assessments. Accessed November 10, 2026.
    2. Consumer Financial Protection Bureau, What is private mortgage insurance? Accessed November 10, 2026.
    3. Consumer Financial Protection Bureau, What is a debt-to-income ratio? Accessed November 10, 2026.
    4. IRS, Publication 936, Home Mortgage Interest Deduction. Accessed November 10, 2026.

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