This calculator helps you estimate the principal and interest (P&I) portion of your monthly mortgage payment for a home in Connecticut.
Connecticut, like all states, has a specific housing market and associated costs, but the core mortgage calculation remains standard across the US.
This calculation does not include property taxes, homeowner's insurance, or Private Mortgage Insurance (PMI), which are often escrowed and added to your total monthly housing expense.
How the Calculation Works
The monthly mortgage payment is calculated using the standard amortization formula. The formula takes into account the loan amount, the interest rate, and the loan term.
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
M = Your total monthly mortgage payment (Principal & Interest)
P = The principal loan amount (the amount you borrow)
i = Your *monthly* interest rate. This is your annual interest rate divided by 12. (e.g., 6.5% annual rate becomes 0.065 / 12 = 0.0054167 monthly rate)
n = The total number of payments over the loan's lifetime. This is your loan term in years multiplied by 12. (e.g., a 30-year loan has 30 * 12 = 360 payments)
Connecticut-Specific Considerations
While this calculator provides the P&I, Connecticut homebuyers should factor in additional costs:
Property Taxes: Connecticut property tax rates vary significantly by town. Research the specific town's mill rate to estimate this cost.
Homeowner's Insurance: Required by lenders, this protects against damage to your home.
Mortgage Recording Fees: Connecticut has specific fees associated with recording your mortgage.
Potential for PMI: If your down payment is less than 20%, you'll likely need Private Mortgage Insurance.
Using this calculator as a starting point will help you understand the core debt servicing cost, enabling more informed budgeting for your Connecticut home purchase.
function calculateMortgage() {
var principal = parseFloat(document.getElementById("principal").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var loanTerm = parseFloat(document.getElementById("loanTerm").value);
var errorMessageDiv = document.getElementById("errorMessage");
var monthlyPaymentResult = document.getElementById("monthlyPayment");
errorMessageDiv.innerHTML = ""; // Clear previous errors
monthlyPaymentResult.innerHTML = "$0.00"; // Reset result
// Input Validation
if (isNaN(principal) || principal <= 0) {
errorMessageDiv.innerHTML = "Please enter a valid loan amount greater than zero.";
return;
}
if (isNaN(interestRate) || interestRate < 0) {
errorMessageDiv.innerHTML = "Please enter a valid annual interest rate (0% or greater).";
return;
}
if (isNaN(loanTerm) || loanTerm <= 0) {
errorMessageDiv.innerHTML = "Please enter a valid loan term in years (greater than zero).";
return;
}
// Calculations
var monthlyInterestRate = interestRate / 100 / 12;
var numberOfPayments = loanTerm * 12;
var monthlyPayment;
if (monthlyInterestRate === 0) {
// Handle 0% interest rate case to avoid division by zero in the main formula
monthlyPayment = principal / numberOfPayments;
} else {
var powerTerm = Math.pow(1 + monthlyInterestRate, numberOfPayments);
monthlyPayment = principal * (monthlyInterestRate * powerTerm) / (powerTerm – 1);
}
// Display Result
if (isFinite(monthlyPayment)) {
monthlyPaymentResult.innerHTML = "$" + monthlyPayment.toFixed(2);
} else {
errorMessageDiv.innerHTML = "Calculation resulted in an invalid number. Please check your inputs.";
}
}