Estimate your monthly payments for both the interest-only draw period and the repayment period.
Monthly Interest-Only Payment:$0.00
Repayment Phase Monthly Payment (P+I):$0.00
Total Interest Paid (Full Term):$0.00
How to Use the HELOC Payment Calculator
A Home Equity Line of Credit (HELOC) is a unique financial tool because its payments change significantly over time. This calculator helps you plan for two distinct phases:
The Draw Period: Usually the first 5-10 years where you can borrow money. Most lenders only require interest payments during this time.
The Repayment Period: Usually the subsequent 10-20 years where you can no longer borrow, and you must pay back both the principal and interest.
Understanding Your Results
Interest-Only Payment: This is calculated by multiplying your current balance by the annual interest rate and dividing by 12. Note that HELOCs usually have variable rates, so this payment will fluctuate if the prime rate changes.
Repayment Phase Payment: This is the "payment shock" many homeowners experience. Once the draw period ends, the loan is amortized over the remaining years. Because you are now paying back the principal balance plus interest, your monthly obligation will rise sharply.
Example Calculation
If you have a $50,000 balance at an 8.5% interest rate:
During the interest-only phase, your payment would be approximately $354.17.
If you then enter a 20-year repayment phase with that same balance and rate, your payment jumps to $433.91.
Disclaimer: This calculator is for estimation purposes only. Actual rates and terms depend on your lender and credit profile. Most HELOCs have variable rates that change with the market.
function calculateHELOC() {
var balance = parseFloat(document.getElementById("helocBalance").value);
var annualRate = parseFloat(document.getElementById("helocRate").value);
var drawYears = parseFloat(document.getElementById("helocDrawPeriod").value);
var repayYears = parseFloat(document.getElementById("helocRepayPeriod").value);
if (isNaN(balance) || isNaN(annualRate) || isNaN(repayYears) || balance <= 0) {
alert("Please enter valid positive numbers for balance, rate, and periods.");
return;
}
// Monthly interest rate
var monthlyRate = (annualRate / 100) / 12;
// 1. Interest Only Payment
var interestOnlyPayment = balance * monthlyRate;
// 2. Repayment Period Payment (Standard Amortization Formula)
// Formula: P * [i(1+i)^n] / [(1+i)^n – 1]
var totalRepayMonths = repayYears * 12;
var repaymentPayment = 0;
if (monthlyRate === 0) {
repaymentPayment = balance / totalRepayMonths;
} else {
repaymentPayment = balance * (monthlyRate * Math.pow(1 + monthlyRate, totalRepayMonths)) / (Math.pow(1 + monthlyRate, totalRepayMonths) – 1);
}
// 3. Total Interest Calculation
var totalInterestDuringDraw = interestOnlyPayment * (drawYears * 12);
var totalPaidDuringRepay = repaymentPayment * totalRepayMonths;
var totalInterestDuringRepay = totalPaidDuringRepay – balance;
var totalInterestCombined = totalInterestDuringDraw + totalInterestDuringRepay;
// Display results
document.getElementById("interestOnlyResult").innerText = "$" + interestOnlyPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("repaymentResult").innerText = "$" + repaymentPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalInterestResult").innerText = "$" + totalInterestCombined.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("helocResultBox").style.display = "block";
}