HELOC Calculator

Estimate home equity line of credit capacity, CLTV, draw-period payments, and repayment-period payments. Everything runs locally in your browser.

Inputs

Include first mortgage balance and other liens ahead of the HELOC.
Use a lender quote, requested line, or the suggested capacity from the results.
Most HELOCs are variable-rate. This model holds the APR constant.

Results

Equity and credit line
Home equity before HELOC-
Suggested max line from CLTV-
Available credit on modeled line-
CLTV: -
Payment estimate
Interest-only draw payment-
Repayment payment-
Stress-tested repayment-
Repayment payment assumes the entered draw balance amortizes over the repayment period.
Interest scenario
Draw-period interest-
Repayment interest-
Total estimated interest-
Assumes no extra draws, no principal payments during draw, and no fees.

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How to Use This HELOC Calculator

  • Enter property and debt values. Use a realistic home value and include your mortgage plus any liens that would count in combined loan-to-value.
  • Choose a CLTV cap. Lenders often set a maximum combined loan-to-value; this tool uses your selected cap to estimate borrowing capacity.
  • Model the line and draw. The HELOC credit limit is the approved line you want to test. The draw balance is the amount currently borrowed or planned.
  • Set APR and periods. Draw-period interest-only payments and repayment-period amortized payments use the APR you enter.
  • Compare the stress test. The optional rate change shows how a higher or lower variable rate could affect repayment payment.

About HELOC Payments and CLTV

A home equity line of credit, or HELOC, is a revolving credit line secured by home equity. The first question is capacity: how much room exists between your current liens and a lender's maximum combined loan-to-value limit. This calculator estimates that room by multiplying your home value by the selected CLTV cap, then subtracting existing mortgage and lien balances. The result is not an approval amount; it is a planning estimate before lender underwriting, appraisal, income review, credit review, and program rules.

The second question is payment. Many HELOCs have a draw period, during which you can borrow, repay, and re-borrow up to the credit limit. Some products allow interest-only payments during this period. The calculator estimates that payment as the current draw balance multiplied by the monthly interest rate. When the repayment period begins, many HELOCs convert to principal-and-interest payments. This page estimates that payment with the standard amortizing loan formula over the repayment period you enter.

HELOC rates are commonly variable, often tied to an index plus a margin. This calculator keeps the rate constant unless you use the stress-test field. It also excludes closing costs, annual fees, minimum draw requirements, early closure fees, balloon payments, taxes, insurance, and interest deductibility. Treat the results as an educational model for comparing scenarios, not as financial, tax, or lending advice.

Formulas and Assumptions

Home equity = home value - existing liens
Suggested max line = max(home value x max CLTV - existing liens, 0)
CLTV with HELOC = (existing liens + HELOC limit) / home value
Interest-only payment = draw balance x APR / 12
Repayment payment = P x r x (1 + r)^n / ((1 + r)^n - 1)

The amortizing payment formula uses principal P, monthly rate r, and repayment months n. If APR is 0%, the repayment payment is principal divided by months.

This tool is for education and planning only. It does not predict approval, future rate changes, property values, lender fees, tax treatment, or legal obligations.

FAQ

What is CLTV for a HELOC?

Combined loan-to-value compares all loans secured by the property to the property value. For example, a mortgage plus HELOC balance of 400,000 on a 500,000 home is 80% CLTV.

Why is the repayment payment higher than the draw payment?

The draw payment shown here is interest-only. The repayment payment includes both principal and interest, amortized over the repayment period.

Can the actual HELOC payment change?

Yes. HELOCs are often variable-rate products, and payments can change when the index rate changes, when you borrow more, or when the draw period ends.

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