HELOC Calculator
Home equity line of credit available from value, balance and LTV.
Available HELOC credit
$125,000.00
85% combined LTV
Home equity
$200,000.00
Max borrowing
$425,000.00
AI Breakdown & Smart Takeaway
Plain-English insight on your numbers
Get a personalized explanation of what these results mean — and how to improve them.
How the HELOC Calculator works
This HELOC Calculator helps homeowners instantly determine how much they can borrow against their home's equity by factoring in the property's current market value, the outstanding mortgage balance, and the lender's maximum loan-to-value (LTV) ratio. It's ideal for anyone exploring home equity financing for renovations, debt consolidation, or major expenses.
The calculator works by first establishing your available home equity — the difference between what your home is currently worth and what you still owe on your mortgage. Lenders don't let you borrow against 100% of that equity; instead, they set a maximum combined loan-to-value (CLTV) limit, typically between 80% and 90% of the home's appraised value. Your potential HELOC credit line is the gap between that CLTV ceiling and your existing mortgage balance, so both inputs matter enormously to the final number.
For example, if your home is valued at $400,000, your mortgage balance is $220,000, and your lender allows an 85% CLTV, the math works out as: ($400,000 × 0.85) − $220,000 = $340,000 − $220,000 = $120,000 available credit line. Change any one of those variables — say the lender tightens LTV to 80% — and your available line drops to $100,000. This sensitivity is why the calculator lets you adjust the LTV threshold: different lenders and different borrower credit profiles produce meaningfully different results.
A common mistake homeowners make is confusing gross equity with borrowable equity. You might have $180,000 in equity, but if your LTV ceiling is 80%, you can only access the portion of that equity that sits above what you still owe — not all of it. Another frequent error is using a stale or inflated home value estimate. Because the calculator is only as accurate as the value you enter, using a recent professional appraisal or a reliable automated valuation model (AVM) rather than a casual Zillow glance will produce far more realistic results.
HELOCs also have a draw period (commonly 10 years) followed by a repayment period, and most carry variable interest rates tied to the prime rate. While this calculator focuses on the credit availability side, understanding the cost side matters too. Homeowners with high-LTV mortgages — such as those who put less than 20% down and haven't built substantial equity yet — will often find their available HELOC line is zero or minimal, which is an important signal to delay borrowing or focus on paying down the primary mortgage first.
Formula
Credit = Home value × max LTV − Mortgage balance
Pro tips
- Use a recent, professional home appraisal rather than an online estimate when entering your home value — lenders will order one anyway, and inflated figures create false expectations about your borrowing capacity.
- Shop lenders for higher CLTV limits: some credit unions and community banks allow 90% or even 95% CLTV versus the standard 80–85%, meaningfully increasing your available line — especially if you have strong credit.
- If your calculated available HELOC is zero or very small, prioritize making extra principal payments on your primary mortgage to build equity faster before applying.
- Keep your LTV well below the lender's maximum ceiling rather than maxing it out — borrowing less preserves a financial cushion if home values decline and protects you from being underwater.
- Check whether your lender charges annual fees, inactivity fees, or early-closure penalties on a HELOC, since a large credit line you don't fully use can still carry ongoing costs.
Key terms
- Home Equity
- — The portion of your property's market value that you actually own, calculated as the home's current value minus any outstanding mortgage or lien balances.
- Loan-to-Value Ratio (LTV)
- — The percentage of a home's appraised value that a lender is willing to let you borrow against, expressed as total debt divided by home value.
- Combined Loan-to-Value (CLTV)
- — The ratio of all loans secured by your home — including your primary mortgage plus any HELOC — relative to the property's appraised value.
- HELOC (Home Equity Line of Credit)
- — A revolving credit facility secured by your home's equity that lets you draw, repay, and re-draw funds up to your approved credit limit during the draw period.
- Draw Period
- — The initial phase of a HELOC — typically 5 to 10 years — during which you can borrow from the line of credit, often making interest-only payments.
- Appraised Value
- — The professionally assessed market value of your home used by lenders to determine the maximum amount they will lend against the property.
