Calculate your estimated monthly mortgage payment for a home in California. This calculator helps you understand principal, interest, taxes, and insurance (PITI).
<input type="number" id="annualPMI" placeholder="e.g., 0.5 (if down payment
Estimated Monthly Payment (PITI)
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Understanding Your California Mortgage Payment (PITI)
Buying a home in California is a significant investment, and understanding your monthly mortgage payment is crucial for financial planning. The standard mortgage payment is often referred to as PITI, which stands for Principal, Interest, Taxes, and Insurance. This calculator helps you estimate your total monthly outlay.
The Components of PITI:
Principal & Interest (P&I): This is the core of your mortgage payment.
Principal: The amount of money you borrowed.
Interest: The cost of borrowing the money, calculated based on your interest rate and the outstanding loan balance. The monthly interest portion is higher at the beginning of the loan and decreases over time.
The formula used to calculate the monthly Principal & Interest payment is:
$ M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]$
Where:
M = Monthly Payment
P = Principal Loan Amount (Home Price – Down Payment)
i = Monthly Interest Rate (Annual Rate / 12)
n = Total Number of Payments (Loan Term in Years * 12)
Property Taxes: In California, property taxes are typically calculated as a percentage of the property's assessed value. While Proposition 13 generally limits property tax increases, the initial rate and subsequent adjustments based on market value or improvements are key. This calculator uses an estimated annual percentage. Your actual tax bill may vary based on your local jurisdiction and assessment practices.
Homeowner's Insurance: This covers damage to your home and personal belongings. The cost varies significantly based on location, coverage levels, and the value of your home. This calculator uses an estimated annual premium.
Private Mortgage Insurance (PMI): If your down payment is less than 20% of the home's purchase price, lenders typically require PMI. This insurance protects the lender in case you default on the loan. PMI is usually paid monthly as a percentage of the loan amount and is removed once you build sufficient equity (typically reaching 20-22% equity).
How the Calculator Works:
Our calculator takes the inputs you provide: home price, down payment, interest rate, loan term, estimated annual property tax rate, annual homeowner's insurance cost, and annual PMI rate (if applicable). It then performs the following calculations:
Calculates the Loan Amount by subtracting your down payment from the home price.
Calculates the monthly interest rate (i) and the total number of payments (n).
Computes the Principal & Interest (P&I) payment using the standard mortgage formula.
Estimates the monthly cost of Property Taxes by dividing the annual estimated tax amount (Home Price * Annual Property Tax Rate) by 12.
Calculates the monthly cost of Homeowner's Insurance by dividing the annual premium by 12.
Calculates the monthly cost of PMI (if applicable) by dividing the annual PMI amount (Loan Amount * Annual PMI Rate) by 12.
Finally, it sums up the monthly P&I, Property Taxes, Homeowner's Insurance, and PMI to provide your estimated Total Monthly Payment (PITI).
Disclaimer: This calculator provides an estimate for informational purposes only. It does not include potential closing costs, HOA fees, or other expenses. Actual mortgage offers and payments may differ. It is highly recommended to consult with a qualified mortgage professional and a California real estate agent for personalized advice and accurate quotes.
function calculateMortgage() {
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTerm = parseFloat(document.getElementById("loanTerm").value);
var annualPropertyTax = parseFloat(document.getElementById("annualPropertyTax").value);
var annualHomeInsurance = parseFloat(document.getElementById("annualHomeInsurance").value);
var annualPMI = parseFloat(document.getElementById("annualPMI").value);
var resultElement = document.getElementById("monthlyPayment");
resultElement.style.color = "#28a745"; // Default to success green
// Input validation
if (isNaN(homePrice) || homePrice <= 0 ||
isNaN(downPayment) || downPayment < 0 ||
isNaN(interestRate) || interestRate <= 0 ||
isNaN(loanTerm) || loanTerm <= 0 ||
isNaN(annualPropertyTax) || annualPropertyTax < 0 ||
isNaN(annualHomeInsurance) || annualHomeInsurance < 0 ||
isNaN(annualPMI) || annualPMI = homePrice) {
resultElement.textContent = "Down payment cannot be equal to or greater than the home price.";
resultElement.style.color = "#dc3545"; // Error red
return;
}
var loanAmount = homePrice – downPayment;
var monthlyInterestRate = (interestRate / 100) / 12;
var numberOfPayments = loanTerm * 12;
var principalInterest = 0;
if (monthlyInterestRate > 0 && numberOfPayments > 0) {
principalInterest = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
} else if (loanAmount > 0) { // Handle 0 interest rate case
principalInterest = loanAmount / numberOfPayments;
}
var monthlyPropertyTax = (homePrice * (annualPropertyTax / 100)) / 12;
var monthlyHomeInsurance = annualHomeInsurance / 12;
var monthlyPMI = 0;
if (downPayment < (homePrice * 0.20)) { // PMI is generally required if down payment is less than 20%
monthlyPMI = (loanAmount * (annualPMI / 100)) / 12;
}
var totalMonthlyPayment = principalInterest + monthlyPropertyTax + monthlyHomeInsurance + monthlyPMI;
resultElement.textContent = "$" + totalMonthlyPayment.toFixed(2);
}