Personal Loan Rate Calculator

Mortgage Affordability Calculator

Use this calculator to estimate how much you might be able to borrow for a mortgage based on your income, debts, and down payment.











Your Estimated Mortgage Affordability

Understanding Mortgage Affordability

Determining how much you can afford for a mortgage is a crucial step in the home-buying process. Lenders consider several factors to assess your borrowing capacity, primarily focusing on your ability to repay the loan. This calculator provides an estimate based on common lending guidelines.

Key Factors:

  • Gross Monthly Income: This is your income before taxes and other deductions. Lenders typically want your total housing payment (including principal, interest, taxes, and insurance – PITI) to be no more than a certain percentage of this amount.
  • Existing Debt Payments: Your recurring monthly debt obligations, such as credit card payments, car loans, student loans, and personal loans, are critical. Lenders use the "debt-to-income ratio" (DTI) to assess your overall debt burden. A common guideline is that your total debt payments (including the new mortgage) should not exceed 43% of your gross monthly income.
  • Down Payment: The larger your down payment, the less you need to borrow, which can improve your affordability and potentially lead to better loan terms and lower monthly payments.
  • Interest Rate: A lower interest rate means less of your monthly payment goes towards interest, allowing you to borrow more for the same monthly payment, or have a lower monthly payment for the same loan amount.
  • Loan Term: A longer loan term (e.g., 30 years vs. 15 years) results in lower monthly payments, making a larger loan amount seem more affordable. However, you will pay more interest over the life of the loan.

How the Calculator Works (Simplified):

This calculator uses a simplified approach. It first estimates the maximum monthly mortgage payment you might qualify for based on a common guideline for the front-end DTI ratio (often around 28-36% of gross monthly income). Then, it subtracts your existing monthly debt payments to find the maximum affordable monthly mortgage payment. Finally, it uses a mortgage payment formula to calculate the maximum loan amount you could borrow given that monthly payment, the interest rate, and the loan term. It also factors in your down payment to estimate the maximum home price you could afford.

Disclaimer: This is an estimate only. Actual loan amounts will be determined by lenders based on a full credit assessment, property appraisal, and specific lending criteria.

function calculateMortgageAffordability() { var monthlyIncome = parseFloat(document.getElementById("monthlyIncome").value); var existingDebt = parseFloat(document.getElementById("existingDebt").value); var downPayment = parseFloat(document.getElementById("downPayment").value); var interestRate = parseFloat(document.getElementById("interestRate").value); var loanTerm = parseFloat(document.getElementById("loanTerm").value); var resultDiv = document.getElementById("result"); resultDiv.innerHTML = ""; // Clear previous results if (isNaN(monthlyIncome) || isNaN(existingDebt) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm)) { resultDiv.innerHTML = "Please enter valid numbers for all fields."; return; } if (monthlyIncome <= 0 || existingDebt < 0 || downPayment < 0 || interestRate <= 0 || loanTerm <= 0) { resultDiv.innerHTML = "Please enter valid positive numbers (except for existing debt which can be zero)."; return; } // — Simplified Affordability Calculations — // Guideline: Max total debt-to-income ratio (DTI) is often around 43% // Guideline: Housing payment (PITI) is often capped at around 36% of gross monthly income var maxHousingPayment = monthlyIncome * 0.36; // Assumption: 36% for PITI var maxTotalDebtPayment = monthlyIncome * 0.43; // Assumption: 43% for total DTI var affordableMortgagePayment = maxHousingPayment – (maxTotalDebtPayment – existingDebt); // Ensure the affordable mortgage payment is not negative if (affordableMortgagePayment 0 && numberOfPayments > 0) { var factor = Math.pow(1 + monthlyInterestRate, numberOfPayments); maxLoanAmount = affordableMortgagePayment * (factor – 1) / (monthlyInterestRate * factor); } else if (affordableMortgagePayment > 0) { // If interest rate is 0, loan amount is simply payment * number of payments maxLoanAmount = affordableMortgagePayment * numberOfPayments; } // Calculate estimated maximum home price var maxHomePrice = maxLoanAmount + downPayment; // — Display Results — var outputHtml = ""; outputHtml += "Maximum Affordable Monthly Mortgage Payment (P&I Estimate): $" + affordableMortgagePayment.toFixed(2) + ""; outputHtml += "Estimated Maximum Loan Amount: $" + maxLoanAmount.toFixed(2) + ""; outputHtml += "Estimated Maximum Home Price (with your down payment): $" + maxHomePrice.toFixed(2) + ""; outputHtml += "Note: This is a simplified estimate. Actual mortgage payments include property taxes, homeowners insurance (PITI), and potentially PMI. Lender approval depends on full credit review and other factors."; resultDiv.innerHTML = outputHtml; }

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