HELOC Calculator
Your available credit line and payments — both during the draw period and after repayment begins
Lenders typically allow 80–85%
Often variable, tied to prime
Interest-only; typically 10
Amortizing; typically 15–20
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Quick summary
Lenders typically allow total debt (mortgage + HELOC) up to 80–85% of home value — that combined loan-to-value limit sets your available credit: a $500,000 home with a $250,000 mortgage at 80% CLTV has $150,000 available. HELOCs run in two phases: an interest-only draw period (typically 10 years, low payment) followed by an amortizing repayment period (typically 15–20 years) where the payment jumps because principal is now due.
Reviewed by Simple Calculators TeamLast reviewed
How to use this calculator
- Enter the inputs requested by the calculator.
- Choose the units or options that match your situation and review the assumptions.
- Run or update the calculation to see the result.
- Review the result, breakdown, and formulas shown on the page.
- Check the inputs, units, dates, and limitations before saving or sharing the result.
Frequently asked questions
How much HELOC can I get?
Home value × max CLTV (usually 80–85%) minus your existing mortgage balance. A $500k home at 80% CLTV supports $400k of total debt; subtract a $250k mortgage and $150k of HELOC room remains — though your income, credit, and the lender's specific policy also gate the final approved amount.
How does a HELOC payment change over time?
During the draw period (commonly 10 years) most HELOCs require interest-only payments on whatever you've borrowed — low and can fluctuate with a variable rate. When the repayment period begins, the loan converts to a fully amortizing payment covering principal too, which is often 2–3× the draw-period payment. Budget for that jump, not just today's bill.
What is combined loan-to-value (CLTV)?
(First mortgage + HELOC balance) ÷ home value. It's the metric HELOC lenders actually underwrite to, since they're in second lien position behind your existing mortgage. Your current CLTV after drawing shows how much cushion remains before hitting the lender's ceiling.
HELOC vs home equity loan vs cash-out refinance — what's the difference?
A HELOC is a revolving credit line at a variable rate, drawn as needed — best for ongoing or uncertain expenses. A home equity loan is a lump sum at a fixed rate — best for one known cost. A cash-out refinance replaces your whole mortgage — worth it mainly if today's rates beat your current one; otherwise it needlessly refinances a low first-mortgage rate.
Key terms
- CLTV
- Combined loan-to-value — all liens on the property divided by its value; the ratio HELOC lenders cap.
- Draw Period
- The years you can borrow against the line, typically interest-only payments.
- Repayment Period
- After the draw period ends — the balance amortizes with principal + interest payments.
- Revolving Credit
- Borrow, repay, and re-borrow within the limit — the HELOC's key difference from a home equity loan.
Methodology, sources & limitations
This page shows the formula, assumptions, and limitations used for this estimate. Rates, thresholds, and other time-sensitive inputs can change, so verify them against the relevant official source before relying on a result.
For our review approach and the primary sources we consult, see the methodology and source policy. If you spot an outdated figure or formula, please contact us with a correction.