The Two Phases of a HELOC Payments

Every HELOC has two distinct stages: the draw period and the repayment period. Your payment obligations — and your payment amounts — are completely different in each phase.

Phase 1

🟦 Draw Period of HELOC

  • Typically lasts 5–10 years (10 years is most common)
  • Borrow, repay, and re-borrow up to your credit limit
  • Most lenders require interest-only minimum payments
  • You pay interest only on what you’ve actually drawn
  • Payments are relatively low and variable
  • Extra principal payments are allowed and encouraged
Phase 2

🟥 Repayment Period of HELOC

  • Typically lasts 10–20 years after the draw period
  • No further borrowing is permitted
  • Monthly payments now include both principal and interest
  • Payments are fully amortized over the remaining term
  • Payments can more than double compared to the draw period
  • Variable rate may continue to fluctuate
Key Insight: During the draw period, your available balance works just like a credit card — as you repay principal, your borrowing power is restored. This revolving flexibility is what makes HELOCs especially popular for long-running home renovation projects or unpredictable ongoing expenses.

 

How to Calculate HELOC Payments

Unlike a traditional fixed mortgage, HELOC payments are not static — they shift based on your outstanding balance, the current interest rate, and which phase you are in. Here is how to calculate each type of payment.

Step 1 — Calculate Your Draw Period (Interest-Only) Payment

During the draw period, your monthly minimum payment covers only the interest accruing on your current outstanding balance. The formula is simple:

📐 Interest-Only Payment Formula
Monthly Payment = Outstanding Balance × (Annual Rate ÷ 12)

Example: You have drawn $30,000 from your HELOC at an 8.00% annual interest rate.

$30,000 × (0.08 ÷ 12) = $30,000 × 0.00667 = $200.00/month

If you had only drawn $15,000 at the same rate, your monthly payment would be just $100. You pay only on what you borrow.

Step 2 — Understand How Your Rate Is Set

Most HELOCs carry a variable interest rate calculated as the U.S. Prime Rate plus a lender margin (typically 0.5% to 2%). As the prime rate rises or falls — often following Federal Reserve policy decisions — your HELOC interest rate and monthly payment adjust accordingly. This means your payment can change month to month, so it is critical to budget for potential rate increases.

Some lenders offer a fixed-rate lock option that allows you to convert a portion or all of your outstanding balance to a fixed rate during the repayment period, providing more payment predictability.

Step 3 — Calculate Your Repayment Period (Principal + Interest) Payment

Once the draw period ends, your outstanding balance becomes a fully amortizing loan. Your lender will calculate a new monthly payment that repays both principal and interest in full over the repayment term. The standard amortization formula applies:

📐 Repayment Period Payment Formula
M = P × [r(1+r)ⁿ] ÷ [(1+r)ⁿ − 1]

Where: M = Monthly payment  |  P = Outstanding principal  |  r = Monthly rate (annual rate ÷ 12)  |  n = Number of remaining months

Example: $30,000 balance, 8.00% rate, 10-year repayment period (120 months):

M = $30,000 × [0.00667(1.00667)¹²⁰] ÷ [(1.00667)¹²⁰ − 1] ≈ $364/month

That’s nearly double the $200 interest-only payment from the draw period — on the same $30,000 balance.

The following table illustrates how HELOC payments compare across different balances and phases at an 8% interest rate, giving you a real-world sense of how payment shock can occur:

Balance Drawn Draw Period Payment (Interest Only) Repayment Payment (10-Year Term) Repayment Payment (20-Year Term)
$15,000 $100/mo $182/mo $126/mo
$30,000 $200/mo $364/mo $251/mo
$50,000 $333/mo $607/mo $418/mo
$100,000 $667/mo $1,213/mo $836/mo

*Estimates based on 8.00% annual interest rate. Rates and payments will vary. Consult a licensed mortgage professional for a personalized quote.

Understanding HELOC Payment Shock

One of the most important — and most frequently misunderstood — aspects of a HELOC is the transition from the draw period to the repayment period. Industry professionals refer to the sudden, dramatic rise in monthly payments as “payment shock.”

If you make interest-only minimum payments throughout the entire draw period and never pay down any principal, you will arrive at the repayment period with your full original balance still outstanding. Your lender will then restructure that balance into a fully amortizing loan, which can cause your monthly payment to more than double in a single month.

⚠️ Pro Tip to Avoid Payment Shock: Even during the draw period when only interest is required, making additional payments toward your principal balance significantly reduces what you’ll owe when repayment begins — and substantially lowers your future monthly payments. Think of it as paying ahead on your own timeline.

Additionally, homeowners should be aware that some HELOCs — particularly older ones or non-QM products — include a balloon payment requirement at the end of the draw period, meaning the entire outstanding balance becomes due at once rather than being amortized over a repayment term. Always review your loan documents carefully and confirm the repayment structure with your lender before signing.

Frequently Asked Questions About HELOC Payments

What is the initial HELOC payment, and when does it start?  Your first HELOC payment is due the month after you make your initial draw from the credit line. During the draw period, most lenders require only an interest-only minimum payment on the amount you have actually borrowed — not on your full approved credit limit. So if you have a $100,000 HELOC but only draw $20,000, your initial payment is based solely on the $20,000 balance. Some lenders offer an introductory “teaser rate” for the first few months that will later reset to the standard variable rate, so always confirm the post-teaser rate before borrowing.
How does an interest-only HELOC payment work? An interest-only HELOC payment means your monthly minimum covers only the interest accruing on your outstanding balance — you are not required to pay down any principal. The formula is straightforward: Outstanding Balance × (Annual Interest Rate ÷ 12). For example, a $30,000 balance at 8% annually generates a monthly interest-only payment of $200. Because most HELOCs carry variable rates tied to the U.S. Prime Rate, this payment can change each month as market rates fluctuate. While interest-only payments keep your costs low during the draw period, the principal balance remains unchanged unless you voluntarily make extra payments.
How does the HELOC repayment period work? When the draw period ends — typically after 10 years — your HELOC transitions into the repayment period, which commonly lasts 10 to 20 years depending on your lender. You can no longer borrow from the credit line, and your outstanding balance is converted into a fully amortizing loan. Monthly payments now include both principal and interest, and they are calculated to pay off the entire remaining balance by the end of the repayment term. Because of this shift, your monthly payment will increase substantially — often more than doubling — compared to the interest-only payments you were making during the draw period. Some lenders allow you to lock in a fixed rate at this stage for payment stability.

Can my HELOC payment change from month to month? Yes. Most HELOCs have variable interest rates tied to the U.S. Prime Rate plus a lender-set margin. When the Federal Reserve adjusts the federal funds rate, the Prime Rate often follows — and your HELOC rate adjusts with it. This means your monthly payment can increase or decrease from month to month based on market conditions, independent of any changes in your own borrowing habits. To manage this uncertainty, some borrowers choose lenders that offer a fixed-rate conversion option, allowing them to lock a portion of their balance at a fixed rate for added predictability.

Is HELOC interest tax-deductible? HELOC interest may be tax-deductible, but only if the funds are used to “buy, build, or substantially improve” the home that secures the line of credit — per IRS guidelines. If you use HELOC proceeds for debt consolidation, a vacation, or other non-home-related purposes, the interest is generally not deductible. Additionally, deductions are subject to the mortgage interest deduction limits established by the Tax Cuts and Jobs Act. Tax laws can change; always consult a qualified tax professional before claiming any deduction related to HELOC interest.

Not Sure How Much Your HELOC Would Cost?

Our licensed mortgage advisors will calculate your personalized draw period and repayment period payments — at no cost and no obligation.

 

References:
ConsumerAffairs. (2025, May 21). HELOC draw period (2026)
RefiGuide. (2026, January). How does HELOC repayment period work in 2026?
RefiGuide. (2026, January 24). How is HELOC interest calculated in 2026?Citizens Bank. (n.d.). HELOC draw period and repayment period. Citizens Learning Center. 

PNC Bank. (n.d.). What is the draw period on a HELOC? PNC Insights. 

 

 

 

Disclaimer: This article is for informational and educational purposes only and does not constitute financial, legal, or tax advice. HELOC rates, terms, and qualification requirements vary by lender and are subject to change. All payment examples are illustrative estimates based on an 8% annual interest rate; actual payments will differ. Consult a licensed mortgage professional, financial advisor, and/or tax consultant before making any borrowing decision. BD