HELOC Payment Calculator

Calculate your home equity line of credit's available equity, interest-only payments during the draw period, and fully amortized payments during the repayment period.

Mathematical Audit

HELOC Payment Formula

A HELOC has two phases: an interest-only 'draw' period where you can borrow against your available equity, and a 'repayment' period where the outstanding balance is amortized into fixed principal-and-interest payments. This calculator estimates payments for both phases.

Available Equity = (Home Value × Max CLTV %) − Existing Mortgage Balance
Draw Amount Used = min(Requested Draw Amount, Available Equity)
Interest-Only Monthly Payment (Draw Period) = Draw Amount Used × (Annual Rate ÷ 12)
Total Interest During Draw = Interest-Only Payment × Draw Period (months)
Repayment Monthly Payment = Draw Amount Used × Monthly Rate ÷ (1 − (1 + Monthly Rate)^−n)
Total Interest Paid = Interest During Draw + Interest During Repayment
Total Paid Over Life = Draw Amount Used + Total Interest Paid

CLTV stands for combined loan-to-value — the maximum percentage of your home's value that all liens (first mortgage plus HELOC) can total, commonly 80-85% for HELOCs. During the draw period (often 10 years), many HELOCs only require interest payments on the amount borrowed; once the repayment period begins (often 10-20 years), the balance is amortized like a standard loan. HELOC rates are typically variable, so actual payments can change over time — this calculator assumes a constant rate for estimation purposes.

Operational Guide

How to Use the HELOC Payment Calculator

1

Enter your home value and existing mortgage balance

These determine how much equity you have available to borrow against.

2

Enter the maximum combined loan-to-value (CLTV) percentage

Most lenders allow a combined loan-to-value of 80-85%; check with your lender for their specific limit.

3

Enter the amount you want to draw and the interest rate

If your requested draw exceeds your available equity, the calculator will flag this and use your maximum available equity instead.

4

Enter the draw period and repayment period

The draw period is how long you can borrow with interest-only payments; the repayment period is how long you have to pay off the balance afterward.

5

Click Calculate

View your available equity, interest-only payment during the draw period, and amortized payment during the repayment period, plus total interest over the life of the HELOC.

Real-World Scenario Example

"A homeowner with a $500,000 home and a $250,000 mortgage balance wants to draw $80,000 from a HELOC with an 85% CLTV limit, 8% interest rate, a 10-year draw period, and a 15-year repayment period."

Inputs

homeValue:500000
existingMortgageBalance:250000
maxCltvPercent:85
drawAmount:80000
interestRate:8
drawPeriodYears:10
repaymentPeriodYears:15

Result

With $175,000 in available equity, the full $80,000 draw is approved. Interest-only payments during the 10-year draw period are about $533/month, and amortized payments during the 15-year repayment period are about $764/month.

Important Disclaimer

This calculator provides estimates for educational and planning purposes only and assumes a constant interest rate for simplicity. Actual HELOC terms, rates (which are typically variable), available credit, and payments are determined by your lender. Consult your lender for exact terms.

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E-E-A-T Genuineness

Sources & References

What is a home equity line of credit (HELOC)?

https://www.consumerfinance.gov/ask-cfpb/what-is-a-home-equity-line-of-credit-heloc-en-205/

Home Equity Line of Credit (HELOC): How It Works

https://www.investopedia.com/mortgage/heloc/