HELOC Calculator
How much home-equity line your value, mortgage balance, and the lender's combined-LTV cap actually support — and what the interest-only payment on a draw would run.
Your available line
Example: $400,000 home, $250,000 owed, 80% cap → $70,000 line.
Equity is not the line
In the worked example — a $400,000 home with $250,000 still owed — the owner holds $150,000 of equity, but the lender's 80% combined-LTV cap prices total home-secured debt at $320,000, leaving an available line of $70,000. Drawing $50,000 at 9% costs about $375.00 a month interest-only during the draw period. The 20% the cap holds back is the lender's cushion against price declines — and, practically, yours too. Every figure is computed by the same tested engine as the calculator above.
Budget past the teaser math
Two payment cliffs deserve attention before drawing: HELOC rates are typically variable, so the interest-only figure moves with the market; and when the draw period ends, the balance begins amortizing over the repayment period, often doubling the payment or more. The interest-only number is a floor, not the cost of the loan — model the amortizing phase with the Loan Calculator before committing.
Frequently asked questions
What is combined loan-to-value (CLTV)?
All debt secured by the home — your mortgage balance plus the HELOC limit — divided by the home’s value. Lenders cap it, commonly at 80–85% (some go higher at higher rates), and the calculator turns that cap into your maximum line: cap × value − mortgage balance.
How do HELOC payments work?
Most HELOCs have a draw period (often 10 years) when you can borrow and typically pay interest only on what is drawn — the payment this calculator shows — followed by a repayment period when the balance amortizes and payments jump, often substantially. Rates are usually variable, so the payment moves with the market.
HELOC or cash-out refinance?
A HELOC adds a flexible second lien and leaves your first mortgage untouched — attractive when your existing rate is low. A cash-out refinance replaces the whole mortgage at today’s rate. When rates are above your current mortgage rate, the HELOC usually wins for moderate amounts; compare with the Refinance Calculator.
What happens if my home value falls?
Your equity shrinks and the lender can freeze or reduce an undrawn line. Amounts already drawn are unaffected but still owed — secured by your home. Borrowing to the absolute maximum leaves no cushion; most planners suggest keeping meaningful equity headroom.
Not financial advice: a general educational estimate. Actual lines depend on credit, income verification, and lender-specific CLTV caps; borrowing against your home puts the home at risk. Values are processed locally in your browser and never transmitted. See the methodology page.