A Home Equity Line of Credit (HELOC) is a revolving line of credit that uses your home as collateral. Unlike a traditional home equity loan, which provides a lump sum, a HELOC functions more like a credit card where you can borrow as much or as little as you need up to a pre-approved limit, pay it back, and borrow again during the "draw period."
How is your HELOC limit calculated?
Lenders typically determine your maximum credit limit based on your Loan-to-Value (LTV) ratio. Most lenders allow for a combined LTV (CLTV) of 80% to 90% of your home's appraised value. The formula used by the calculator above is:
(Home Value × Max LTV %) – Current Mortgage Balance = HELOC Limit
Example Calculation:
Suppose your home is worth $400,000 and you still owe $250,000 on your primary mortgage. If your lender allows an 85% LTV limit:
1. 85% of $400,000 = $340,000
2. $340,000 – $250,000 = $90,000
Your maximum HELOC line would be $90,000.
Factors That Affect Approval
Credit Score: Higher scores usually result in better interest rates and higher LTV allowances.
Debt-to-Income (DTI) Ratio: Lenders want to ensure you have enough monthly income to cover new payments.
Home Appraisal: Professional appraisals are required to verify the current market value of your property.
Draw Period vs. Repayment Period
Most HELOCs have two distinct phases. During the Draw Period (usually 10 years), you can access funds and often pay only interest. Once the Repayment Period begins (usually 15-20 years), you can no longer borrow money and must pay back both principal and interest, which can significantly increase your monthly payments.
function calculateHELOC() {
var homeValue = document.getElementById("heloc_home_value").value;
var mortgageBalance = document.getElementById("heloc_mortgage_balance").value;
var ltvLimit = document.getElementById("heloc_ltv_limit").value;
var resultArea = document.getElementById("heloc-result-area");
var outputText = document.getElementById("heloc_output_text");
// Clear previous results
outputText.innerHTML = "";
resultArea.style.display = "none";
// Validate inputs
if (homeValue === "" || mortgageBalance === "" || ltvLimit === "" || homeValue <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
var val = parseFloat(homeValue);
var bal = parseFloat(mortgageBalance);
var ltv = parseFloat(ltvLimit) / 100;
// Calculation Logic
var totalAllowedEquity = val * ltv;
var maxHELOC = totalAllowedEquity – bal;
resultArea.style.display = "block";
if (maxHELOC <= 0) {
outputText.innerHTML = "Limit Result: $0Based on your current mortgage balance and the LTV limit, you do not have sufficient equity to open a HELOC at this time. Most lenders require your total debt to be below " + (ltv * 100) + "% of the home's value.";
} else {
var formattedResult = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(maxHELOC);
var formattedTotal = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(totalAllowedEquity);
outputText.innerHTML = "Estimated HELOC Limit:" + formattedResult + "" +
"" +
"Your lender allows a total borrowing limit of " + (ltv * 100) + "% (" + formattedTotal + "). " +
"After subtracting your current mortgage balance of " + new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(bal) +
", your remaining available credit is " + formattedResult + ".";
}
}