HELOC Calculator
See your interest-only draw-period payment and your principal-plus-interest repayment payment for a home equity line of credit.
Example
On a $50,000 HELOC balance at 8.5% APR with a 20-year repayment term:
- Interest-only payment (draw period): $50,000 × (0.085 / 12) = $354.17/mo
- Principal + interest (repayment): $50,000 × 0.0070833 / (1 - 1.0070833-240) = $433.91/mo, for about $54,138.79 in total interest.
With a $400,000 home at 85% max LTV and a $250,000 mortgage: max borrowable = $340,000, leaving $90,000 in available credit.
How it works
Enter your HELOC balance, APR, and the repayment term to get both the interest-only payment and the fully amortizing principal-plus-interest payment. Add your home value, max LTV, and mortgage balance to see how much credit you can still access.
Good to know
This HELOC Calculator estimates the two very different monthly payments a home equity line of credit produces: the low interest-only payment you typically make during the draw period, and the larger principal-plus-interest payment that kicks in once the line enters its repayment phase. It also estimates how much credit you could tap based on your home's value, a lender's maximum loan-to-value cap, and your existing mortgage balance. It's aimed at homeowners weighing a HELOC for renovations, debt consolidation, or a cash cushion who want to see the future payment shock before signing.
Reach for it when you're comparing lender offers, deciding how much of a line to actually draw, or stress-testing whether you can afford the repayment-period bill. Enter your expected balance, APR, repayment term, and draw length to get both payments side by side; the available-credit section is independent and just needs home value, max LTV, and your current mortgage.
To read the results: the headline number reflects the mode toggle (draw vs repay), while the four stats always show interest-only per month, principal-plus-interest per month, total interest paid across the draw period, and total interest over the full repayment term. The bars show your max borrowable amount (home value times LTV) and the credit remaining after subtracting your mortgage. A large gap between the interest-only and P+I figures is your signal of how much the payment will jump later.
One important caveat: most real HELOCs carry variable rates tied to an index like the prime rate, so the single APR you enter is only a snapshot. Run the numbers again at a higher rate to see how a few rate hikes would change your payment, and remember that paying only interest during the draw period leaves the full principal waiting for you at repayment.
Frequently asked questions
What is the difference between the interest-only and principal-plus-interest payment?
During the draw period most HELOCs let you pay only the interest on your balance (balance times the monthly rate), which keeps payments low. When the repayment period begins you must pay both principal and interest, so the payment is calculated as a fully amortizing loan over the remaining term and is higher.
How is my available HELOC credit calculated?
Lenders cap your combined loan-to-value (CLTV). This tool computes max borrowable as home value times your max LTV percentage, then subtracts your existing mortgage balance. The remainder is the credit you may be able to access, subject to the lender's actual limits and underwriting.
Is my data uploaded anywhere?
No — this calculator runs entirely in your browser; nothing is uploaded.
Is this financial advice?
No. These are educational estimates — consult a qualified financial professional before making decisions.
People also ask
What is a HELOC and how does it work?
A home equity line of credit (HELOC) is a revolving credit line secured by the equity in your home. It usually has a draw period during which you can borrow and repay repeatedly, often with interest-only minimums, followed by a repayment period when you pay down the principal plus interest and can no longer draw new funds.
How long is the typical HELOC draw period and repayment period?
Many HELOCs have a draw period of around 10 years followed by a repayment period of roughly 10 to 20 years, though exact lengths vary by lender. The draw period is when you can access funds; the repayment period is when the balance amortizes.
What credit score do you need for a HELOC?
Lenders commonly look for a credit score in the mid-600s or higher, along with sufficient home equity and a manageable debt-to-income ratio. Requirements differ by lender, and a stronger profile can affect the rate and credit limit offered.
Is HELOC interest tax deductible?
Under current U.S. rules, HELOC interest may be deductible only when the funds are used to buy, build, or substantially improve the home that secures the loan, and subject to overall mortgage debt limits. Tax situations vary, so consult IRS guidance or a tax professional.
What is the difference between a HELOC and a home equity loan?
A home equity loan gives you a lump sum at a typically fixed rate with set monthly payments, while a HELOC is a revolving line you draw from as needed, usually at a variable rate. A HELOC offers flexibility; a home equity loan offers payment predictability.
Can my HELOC payment go up over time?
Yes. Most HELOCs have variable rates that move with an index such as the prime rate, so payments can rise or fall as rates change. Payments also typically increase when the line shifts from the interest-only draw period to the principal-plus-interest repayment period.
What does combined loan-to-value (CLTV) mean for a HELOC?
Combined loan-to-value compares all loans secured by your home, including your mortgage and the new HELOC, against the home's value. Lenders cap CLTV at a maximum percentage, so your available HELOC credit is roughly the home value times that cap minus your existing mortgage balance.
What happens to a HELOC if I sell my house?
A HELOC is secured by your home, so it must generally be paid off at closing when you sell, typically from the sale proceeds. Any remaining balance reduces the cash you walk away with after the mortgage and other liens are settled.
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