HELOC Calculator
Estimate how large a home equity line of credit you could qualify for from your home value, mortgage balance and your lender's combined loan-to-value limit.
Frequently Asked Questions
How much HELOC can I get?
Up to your lender’s combined loan-to-value (CLTV) limit minus your current mortgage balance. For example, at an 85% CLTV on a $400,000 home, you could borrow up to $340,000 across all loans, less what you still owe.
What is CLTV?
Combined loan-to-value is the total of all loans secured by your home divided by its value. Lenders usually cap CLTV around 80% to 90% for a HELOC.
Does this guarantee approval?
No. It is an estimate based on equity and CLTV only. Lenders also check your income, credit score, debt-to-income ratio and property type before approving a line.
Understanding the HELOC Calculator
A HELOC (home equity line of credit) calculator estimates how much you could borrow against your home. Enter your current home value, outstanding mortgage balance, and the maximum combined loan-to-value (CLTV) your lender allows — typically 80% to 90%. The tool instantly shows your available credit line, current home equity, and your current and projected CLTV. You can optionally add a drawn amount and interest rate (APR) to see the interest-only monthly payment during the draw period. Everything runs entirely in your browser, is fully currency-aware, and stays private. Results are estimates — actual limits depend on credit, income, and lender underwriting.
How it works
The calculator works from three core figures. Your current equity is simply home value minus mortgage balance — the portion of the home you truly own. The maximum a lender will lend across all loans is your home value multiplied by their CLTV cap. Subtracting your existing mortgage from that maximum gives the available HELOC credit line. Current CLTV shows how leveraged you already are (mortgage divided by home value). If you enter a draw amount and APR, it estimates the interest-only payment lenders typically charge during the draw period. The draw is capped to your available line, and a projected new CLTV reflects the additional borrowing.
Worked example
Suppose your home is worth $400,000, you owe $220,000, and your lender caps CLTV at 85%. Your equity is $180,000. The maximum borrowable is $400,000 × 0.85 = $340,000, so your available HELOC is $340,000 − $220,000 = $120,000. Your current CLTV is 55%. If you draw $30,000 at an 8.5% APR, the interest-only monthly payment is about $213, and your CLTV rises to roughly 62.5%.
Tips & common mistakes
- Most lenders cap combined loan-to-value (CLTV) between 80% and 90% — check your lender's actual limit before relying on the estimate.
- Keep your CLTV well below the cap; lower leverage usually earns a better interest rate and approval odds.
- HELOCs typically have a variable rate, so budget for payments rising if benchmark rates increase.
- During the draw period you often pay interest only, but payments jump once principal repayment begins — plan ahead.
- Lenders also weigh your credit score, income, and debt-to-income ratio, so a large equity cushion alone does not guarantee approval.
- Use a recent, realistic home value — an inflated estimate overstates the credit line a lender will actually offer.
Related tools
Reviewed by the TopOpenTools editorial team · Last updated June 2026. These tools provide general estimates for educational purposes only and are not financial, tax, insurance, investment, or medical advice. Verify important decisions with a qualified professional.