HELOC Calculator
Estimate your available credit line and payment during both the draw period and repayment period of a HELOC.
In two sentences: A HELOC calculator estimates your available credit line and monthly payment on a home equity line of credit, where the national average rate sits around 7.2%–7.5% in mid-2026 and borrowing power depends on your home’s value, your existing mortgage balance, and your lender’s maximum combined loan-to-value ratio. This guide breaks down the formula, current rate data, and worked examples so you understand exactly how much you could borrow and what it would cost.
What Is a HELOC Calculator?
A HELOC (Home Equity Line of Credit) calculator estimates two things: how much you can borrow against your home’s equity, and what your monthly payment would look like at current variable rates. Unlike a traditional loan, a HELOC works like a credit card secured by your home — <cite index=”46-1″>you can borrow as little or as much as you need, up to your approved credit line, during a draw period, and your available credit increases again as you pay down principal</cite>.
The HELOC Borrowing Power Formula
Available Equity = Home Value − Current Mortgage Balance
Maximum HELOC Line = (Home Value × Max Combined LTV%) − Current Mortgage Balance
The payment formula during repayment
M = P × [ r(1 + r)^n ] / [ (1 + r)^n − 1 ]
M = monthly payment
P = amount drawn from the HELOC
r = monthly interest rate (variable, tied to Prime rate)
n = repayment period in months
Current HELOC Interest Rates (2026)
<cite index=”41-1″>The national average HELOC interest rate is 7.44% as of late July 2026, according to Bankrate’s survey of the nation’s largest home equity lenders</cite>. <cite index=”38-1″>The national average for a HELOC specifically was 7.23% according to Curinos data, with a 2026 low of 7.19% observed in mid-May</cite>. <cite index=”38-1″>Both figures are based on applicants with a minimum credit score of 780 and a maximum combined loan-to-value ratio (CLTV) of less than 70%</cite> — borrowers with lower credit or higher CLTV should expect higher quoted rates.
<cite index=”38-1″>Most HELOCs are variable-rate products, meaning their interest rate is tied to an external benchmark like the Prime rate, with lenders adding a margin based on the borrower’s risk profile</cite>.
Worked Examples
Example 1: Calculating your maximum HELOC line
<cite index=”42-1″>A homeowner with a 740 credit score, a $400,000 home value, and a $200,000 outstanding mortgage balance could potentially secure a HELOC with an APR around 8.5%, allowing access to a credit limit of up to $100,000, assuming a combined loan-to-value ratio of 75%</cite>:
Max loan at 75% CLTV = $400,000 × 0.75 = $300,000
Available HELOC = $300,000 − $200,000 mortgage balance = $100,000
Example 2: A more competitive scenario at 80–90% LTV
<cite index=”45-1″>On a $500,000 home with a $280,000 remaining mortgage, borrowing up to 80% LTV yields $400,000 − $280,000 = $120,000 available, while some lenders offering up to 90% LTV for borrowers with 740+ credit scores would allow $450,000 − $280,000 = $170,000 available</cite> — a $50,000 difference purely based on the lender’s maximum LTV policy.
Example 3: Monthly payment during repayment
If you draw $60,000 from a HELOC at 7.44% APR and repay it over a 15-year (180-month) repayment period after the draw period ends:
Monthly rate = 0.0744 ÷ 12 = 0.0062
n = 180 payments
Monthly payment ≈ $557
Total interest paid ≈ $40,260
Step-by-Step: How to Use a HELOC Calculator
- Enter your home’s current estimated value.
- Enter your remaining mortgage balance.
- Enter your lender’s maximum combined loan-to-value ratio (typically 75–90%) to see your maximum available credit line.
- Enter a draw amount and current variable rate estimate to see an example monthly payment.
- Remember HELOC rates are variable — re-run your numbers periodically as rates change, since <cite index=”45-1″>a Prime rate shift of even 1 percentage point directly shifts your HELOC rate by the same amount, with no refinancing required</cite>.
HELOC vs. Home Equity Loan: The Key Difference
<cite index=”39-1″>Home equity loans and HELOCs typically have similar rates to one another, though which is cheaper can shift from year to year</cite>. The structural difference matters more than the rate gap: <cite index=”44-1″>a HELOC lets you borrow money as needed up to a certain limit, paying interest only on what you draw at a variable rate, which tends to suit borrowers with recurring expenses or multiple projects over time</cite> — while a home equity loan delivers a single lump sum at a fixed rate.
Smart Ways to Use a HELOC Calculator Before You Apply
A HELOC calculator is most useful run twice — once to see your maximum available credit line, and again to model a realistic draw amount and repayment scenario, since approval for a large credit line doesn’t mean you should draw all of it. Because HELOC rates are variable, running your HELOC calculator at a few different rate assumptions (your current rate, plus 1–2 percentage points higher) shows you how much your payment could rise if rates increase during your draw or repayment period.
A responsible HELOC calculator workflow
- Use a HELOC calculator to find your maximum available credit line based on your home value, mortgage balance, and lender’s max CLTV.
- Decide how much you actually need to draw for your specific purpose, rather than treating the maximum as a target.
- Re-run the HELOC calculator with that smaller draw amount to see a realistic monthly payment during repayment.
- Stress-test the result by adding 1–2 percentage points to the rate, since <cite index=”38-1″>HELOC rates are variable and tied to external benchmarks that can rise over the life of the line</cite>.
This approach keeps a HELOC calculator’s output grounded in what you’ll actually borrow, not just what you’re theoretically approved for.
Frequently Asked Questions
<cite index=”39-1″>Homeowners typically need 15% to 20% home equity to qualify, and can often borrow as much as 80% of that equity combined with their existing mortgage</cite>.
<cite index=”38-1″>Most HELOCs carry variable rates tied to an external index like the Prime rate</cite>, meaning your monthly payment can rise or fall as market rates change — unlike a fixed-rate home equity loan.
<cite index=”43-1″>HELOCs typically have a 10-year draw period during which you can borrow and repay repeatedly, with minimum payments generally lower than during the repayment period that follows</cite>.
Yes — <cite index=”38-1″>both your credit score and your combined loan-to-value ratio are key inputs lenders use to set your specific margin above the base rate</cite>, and the national average rates cited above assume a strong 780+ credit score.
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In summary, a HELOC calculator is most valuable when it accounts for both your maximum borrowing power (based on your combined LTV) and current variable rate data, since HELOC rates and available credit lines can shift meaningfully as home values and Prime rates change.
Note: This calculator and article are provided for general educational and informational purposes only and do not constitute financial or lending advice. HELOC rates, terms, and maximum LTV limits vary by lender and change frequently. Always confirm current terms directly with your lender.