Estimate your HELOC payment and how much you can borrow. See your interest-only draw-period payment, the amortizing repayment payment, available credit at 85% CLTV, and total interest.
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A HELOC (Home Equity Line of Credit) lets you borrow against your home's equity like a credit card: a revolving line you can draw from as needed. But its payment structure trips up many borrowers, because it changes partway through. This calculator estimates the two payments you need to plan for — plus how much you can actually borrow.
A HELOC has two phases. During the draw period (commonly 10 years) you can borrow and repay freely, and lenders usually require only interest-only payments — low, but they don't reduce the balance. When the draw period ends, the repayment period (commonly 20 years) begins: no more borrowing, and your payment jumps because it now includes principal. Many borrowers are surprised by that increase.
Enter your home value, current mortgage balance, the HELOC balance you plan to carry, and the rate. The tool estimates your available credit (based on the lender's combined loan-to-value limit, typically 85%), your interest-only draw payment, your amortizing repayment payment, and the total interest over the life of the line.
When to use this calculator
Estimate your interest-only HELOC payment during the draw period.
See how much your payment jumps when the repayment period begins.
Calculate how much you can borrow against your home's equity.
Check available credit at an 85% combined loan-to-value limit.
Compare HELOC payments at different interest rates.
Plan for the payment shock at the end of a 10-year draw period.
Estimate total interest over the full life of the line.
See the borrowing limit after subtracting your first mortgage.
Budget a HELOC-funded home renovation or debt consolidation.
Compare a HELOC's interest-only cost against a fixed home-equity loan.
HELOC interest-only vs repayment payment (10-yr draw, 20-yr repayment)
Balance
Rate
Interest-only (draw)
Repayment (P&I)
Monthly jump
$25,000
8.5%
$177
$217
$40
$50,000
8.5%
$354
$434
$80
$75,000
8.5%
$531
$651
$120
$100,000
8.5%
$708
$868
$160
$100,000
10.0%
$833
$965
$132
Illustrative, principal and interest only. Draw-period payment is interest only; repayment amortizes the balance over 20 years. HELOC rates are typically variable, so real payments can change.
How it works
How a HELOC payment works
Available credit = Home value × CLTV limit − mortgage balance
Draw period payment = Balance × (APR ÷ 12) (interest only)
Repayment payment = Balance amortized over the repayment term (principal + interest)
The draw-period payment is low because you are only covering interest — the balance does not shrink. When repayment begins, principal is added and the payment rises, sometimes sharply.
Repayment period (20 yr): amortizing the same $50,000 = $434/month.
That is an $80/month jump — and if you had drawn more, or rates rose, the increase would be larger.
How much can you borrow?
Lenders cap your combined loan-to-value (CLTV) — your first mortgage plus the HELOC — usually around 85% of the home's value (some go to 90%).
Home value
Mortgage
85% CLTV limit
Available HELOC
$400,000
$250,000
$340,000
$90,000
$500,000
$300,000
$425,000
$125,000
$600,000
$200,000
$510,000
$310,000
Watch-outs before you draw
Variable rate: Most HELOCs are tied to the prime rate, so your payment can rise (or fall) as rates move. Budget for higher rates.
Payment shock: Plan now for the repayment-period increase, especially if you carry a large balance to the end of the draw period.
Your home is collateral: A HELOC is secured by your house — default can lead to foreclosure. Borrow conservatively.
Interest deductibility: HELOC interest is only tax-deductible if the funds are used to buy, build, or substantially improve the home securing the loan, and only if you itemize.
Disclaimer
Educational estimate. Actual HELOC terms — draw and repayment lengths, CLTV limits, margins, rate caps, and fees — vary by lender, and rates are typically variable. This tool models principal and interest only. Confirm figures with your lender.
Example: $500,000 home, $300,000 mortgage, $50,000 drawn at 8.5%
Available credit: $500,000 × 85% − $300,000 = $125,000.
Draw period (interest-only): $50,000 × 8.5% ÷ 12 = about $354/month.
Repayment period (20-year amortization): about $434/month.
The payment rises about $80/month when repayment begins; total interest ≈ $96,600.
About $354/month interest-only, then $434/month
Frequently asked questions
How is a HELOC payment calculated?
During the draw period, most HELOCs require interest only: balance × (APR ÷ 12). So a $50,000 balance at 8.5% is about $354/month. During the repayment period, the balance amortizes over the remaining term, adding principal and raising the payment (to about $434/month in that example).
How much can I borrow with a HELOC?
Lenders limit your combined loan-to-value (CLTV) — first mortgage plus HELOC — usually to about 85% of your home's value. So available credit ≈ home value × 85% − mortgage balance. On a $500,000 home with a $300,000 mortgage, that is roughly $125,000.
What is the difference between the draw and repayment periods?
The draw period (typically 10 years) is when you can borrow and usually pay interest only. The repayment period (typically 20 years) begins after — you can no longer borrow, and your payment rises because it now includes principal. The transition often causes a noticeable payment increase.
Why does my HELOC payment go up later?
Because interest-only draw-period payments don't reduce the balance. When repayment starts, the entire balance must be paid off over the remaining term, so principal is added to every payment. If you carried a large balance, the jump can be significant — plan for it in advance.
Is a HELOC rate fixed or variable?
Most HELOCs have a variable rate tied to the prime rate plus a margin, so your payment can change as rates move. Some lenders offer a fixed-rate conversion option for part of your balance. Because rates vary, budget for the possibility of higher payments.
HELOC vs home equity loan — what's the difference?
A home equity loan gives you a lump sum at a fixed rate with fixed payments. A HELOC is a revolving line you draw from as needed, usually at a variable rate with interest-only draw payments. A HELOC offers flexibility; a home equity loan offers payment certainty.
Is HELOC interest tax-deductible?
Only if you use the money to buy, build, or substantially improve the home that secures the HELOC — and only if you itemize deductions. Interest on a HELOC used for other purposes (paying off cards, a car, tuition) is not deductible under current federal rules.
Can I lose my home with a HELOC?
Yes — a HELOC is secured by your home, so defaulting can lead to foreclosure, just like a first mortgage. Because it puts your home at risk and payments can rise, borrow only what you can comfortably repay even if rates increase.
Finance calculator with its formula verified automatically against CFPB — What is a home equity line of credit (HELOC)?, per our editorial policy and methodology.
Updates
Updated: July 2026. Parameters are verified periodically against the cited sources.
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Limitations
Indicative results. For critical decisions, consult a professional.
📌 How to cite this calculator
Rodríguez, M. (2026). HELOC Payment Calculator. Hacé Cuentas. https://hacecuentas.com/en/heloc-home-equity-line-payment-calculator
Content licensed under CC-BY 4.0 — reuse it citing the source with a link to Hacé Cuentas.
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