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HELOC Calculator

This HELOC calculator estimates the maximum line, remaining equity, an interest-only payment, and an amortizing principal-and-interest payment.

Typical cap is 80%. Combined LTV includes the mortgage plus the HELOC.

The portion of the line you plan to use for payment estimates.

HELOC estimate

Maximum HELOC line
$70,000.00
Current equity
$150,000.00
Remaining equity after max line
$80,000.00
Interest-only monthly
$212.50
Amortizing P&I monthly
$371.96
Combined LTV cap used
80.0%

This is not a loan offer, pre-approval, or financial advice. Lenders set their own rates, fees, credit requirements, and combined LTV caps.

Advertiser disclosure: A finance partner link will show here when it is live. We may earn a commission if you use it. This is not a loan offer, and the calculator result does not change.

How to use

  1. Enter home value, current mortgage balance, and the lender’s combined loan-to-value cap.
  2. Enter the rate, the amount you would draw, and the repayment term in years.
  3. Compare the interest-only payment with the fully amortizing payment. This is an estimate, not a loan offer.

Formula

Maximum line = home value × combined LTV − mortgage balance. Interest-only payment = draw × annual rate ÷ 12. The amortizing payment uses the standard monthly loan formula on the draw over the term you enter.

Example. A $400,000 home with a $200,000 mortgage and an 80% cap supports a $120,000 line. A $20,000 draw at 8% is about $133 a month interest-only ($20,000 × 0.08 ÷ 12).

Frequently asked questions

What is combined loan-to-value (CLTV)?

CLTV is all loans secured by the home—usually the first mortgage plus the HELOC—divided by the home’s value. Many lenders cap combined LTV around 80–85%. This tool uses the percentage you enter (default 80%).

How is the maximum HELOC line calculated?

Maximum line equals home value times the max combined LTV percent, minus the current mortgage balance. If that number is negative, no line is available under those assumptions. Lenders may also subtract other liens or require a lower cap.

What does remaining equity mean here?

Current equity is home value minus the mortgage. Remaining equity after the max line is what is left if you borrowed the full HELOC: home value minus mortgage minus max line, which equals the unencumbered share below the CLTV cap.

How is the interest-only monthly payment calculated?

Interest-only payment is the draw amount times the annual rate, divided by 12. It assumes a simple variable-rate draw period with no principal reduction. HELOC rates often change, so this is a snapshot at the rate you enter.

How is the amortizing principal-and-interest payment calculated?

It uses a standard fully amortizing loan formula on the draw amount over the repayment years you enter, with monthly compounding. Many HELOCs later convert from interest-only to amortizing; this models that repayment-style payment.

Is this a loan offer or pre-approval?

No. Quick Tools does not make loans, pull credit, or contact lenders. Figures ignore origination fees, annual fees, insurance, taxes, and rate caps. Talk to a licensed lender for actual eligibility and disclosures.

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