Financial Breakdown:
Monthly Gross Income: $0.00
Total Monthly Debt: $0.00
function calculateDTI() {
// Get Input Values
var annualIncome = parseFloat(document.getElementById('annualIncome').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var car = parseFloat(document.getElementById('carPayment').value);
var student = parseFloat(document.getElementById('studentLoan').value);
var credit = parseFloat(document.getElementById('creditCard').value);
var other = parseFloat(document.getElementById('otherDebt').value);
// Validation: Treat NaNs as 0, but check income
if (isNaN(annualIncome)) annualIncome = 0;
if (isNaN(rent)) rent = 0;
if (isNaN(car)) car = 0;
if (isNaN(student)) student = 0;
if (isNaN(credit)) credit = 0;
if (isNaN(other)) other = 0;
// Edge case: No income entered
if (annualIncome <= 0) {
alert("Please enter a valid Gross Annual Income greater than zero.");
return;
}
// Calculations
var monthlyIncome = annualIncome / 12;
var totalMonthlyDebt = rent + car + student + credit + other;
var dtiRatio = (totalMonthlyDebt / monthlyIncome) * 100;
// Formatting Results
var dtiFormatted = dtiRatio.toFixed(2) + "%";
var monthlyIncomeFormatted = "$" + monthlyIncome.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
var totalDebtFormatted = "$" + totalMonthlyDebt.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Status Logic
var statusHtml = "";
if (dtiRatio <= 36) {
statusHtml = "Healthy DTI Your debt is manageable. Lenders typically view this ratio favorably.";
} else if (dtiRatio > 36 && dtiRatio <= 43) {
statusHtml = "Moderate DTI You are approaching the limit most mortgage lenders accept (43%). Consider reducing debt.";
} else {
statusHtml = "High DTI Your debt level is high relative to your income. It may be difficult to qualify for new loans.";
}
// Update DOM
document.getElementById('dtiValue').innerHTML = dtiFormatted;
document.getElementById('monthlyIncomeDisplay').innerHTML = monthlyIncomeFormatted;
document.getElementById('totalDebtDisplay').innerHTML = totalDebtFormatted;
document.getElementById('dtiStatusBox').innerHTML = statusHtml;
// Show Result
document.getElementById('dtiResult').style.display = "block";
}
Understanding Your Debt-to-Income (DTI) Ratio
The Debt-to-Income (DTI) ratio is one of the most critical metrics lenders use to assess your ability to repay a loan. Whether you are applying for a mortgage, a car loan, or a personal line of credit, your DTI gives financial institutions a snapshot of your financial health by comparing your monthly debt obligations to your gross monthly income.
How DTI is Calculated
The formula for calculating DTI is straightforward but powerful. It is the sum of all your monthly debt payments divided by your gross monthly income (income before taxes and deductions), multiplied by 100 to get a percentage.
Note that "Total Monthly Debt" typically includes:
Rent or Mortgage payments (including property tax and insurance)
Car loan payments
Student loan payments
Minimum credit card payments
Alimony or child support payments
It generally does not include variable expenses like groceries, utilities, or entertainment.
What is a Good DTI Ratio?
While requirements vary by lender and loan type, here are general guidelines:
36% or less: This is considered an excellent DTI. Most lenders will view you as a low-risk borrower.
36% to 43%: This range is manageable but getting tighter. 43% is often the highest DTI a borrower can have to get a Qualified Mortgage.
Above 43%: Lenders may deny loan applications because this suggests you may have trouble making monthly payments if financial trouble arises.
Front-End vs. Back-End DTI
In mortgage lending, you may hear about two types of ratios:
Front-End Ratio: This only calculates the percentage of income that goes toward housing costs (mortgage, insurance, HOA fees). Lenders prefer this to be under 28%.
Back-End Ratio: This includes housing costs plus all other debts (credit cards, loans). This is the number calculated by the tool above, and lenders prefer it under 36% (though up to 43% is common for FHA loans).
How to Lower Your DTI
If your calculation shows a high DTI, you can improve it by either increasing your income or reducing your debt. The most effective strategy is usually the "Snowball Method" or "Avalanche Method" to pay off credit cards and personal loans, as these often have the highest impact on your monthly obligations compared to the total balance.