HELOC Payment Calculator

A borrower who withdraws $50,000 on a Home Equity Line of Credit at a 7.2% APR might pay only $300 per month during the first 10 years. After that draw period closes, the same $50,000 balance can require roughly $398 per month to cover a 20-year amortized repayment schedule. Because a HELOC divides borrowing into two distinct phases, a dedicated HELOC payment calculator is the most reliable way to estimate your real monthly cost before you borrow.

This article is for informational purposes only and does not constitute financial advice.

How Does a HELOC Payment Calculator Work?

A HELOC payment calculator runs two separate formulas depending on which phase of the loan you are in. During the draw period, it estimates interest-only payments based on your outstanding balance and current APR. During the repayment period, it amortizes the remaining principal over the months left in your term.

To return an accurate estimate, the calculator uses four inputs:

• Current balance – the amount you have actually drawn, not your total credit limit.
• APR – the annual percentage rate, typically variable and indexed to the prime rate.
• Draw period – usually 5 to 10 years, when most lenders require interest-only minimums.
• Repayment period – commonly 10 to 20 years, when you must repay both principal and interest.

How Are Interest-Only HELOC Payments Calculated?

During the draw period, you can withdraw, repay, and re-borrow funds up to your limit. Most lenders only require monthly interest on the outstanding balance.

You can calculate the payment manually:

Interest-Only Payment = Current Balance × (APR ÷ 12)

Using a $50,000 balance at 7.2% APR: $50,000 × (0.072 ÷ 12) = $300 per month

Because HELOC APRs are usually variable, this figure adjusts whenever your rate changes–often every 6 or 12 months.

What Happens During the Repayment Period?

Once the draw period ends, your credit line freezes. You can no longer take out funds, and the lender recalculates your payment to zero out the remaining balance by the end of the term.

The repayment phase uses standard amortization. Each payment now covers interest plus principal reduction. The formula is:

Payment = P × [r(1+r)^n] ÷ [(1+r)^n – 1]

Where:

• P = remaining principal
• r = monthly interest rate (APR ÷ 12)
• n = total number of months in the repayment period

Applying the same $50,000 balance at 7.2% APR over 240 months produces a monthly payment of approximately **$398**.

Why Do HELOC Payments Change After the Draw Period?

HELOCs are not structured like fixed home equity loans. The shift from interest-only to fully amortized payments is the leading cause of payment shock among homeowners. If you made only minimum payments for the first decade, your principal balance never dropped. When repayment begins, the lender compresses the full payoff into the remaining term.

On top of that structure change, most HELOCs carry variable rates. An upward rate movement during either phase can raise your bill even if your outstanding balance stays flat.

Example: $50,000 HELOC at 7.2% APR

The table below shows the monthly difference between the two phases of a typical HELOC opened in 2026.

If you pay down $10,000 of principal during the draw period, the amortized payment drops because the new balance entering repayment is $40,000 rather than $50,000.

What Factors Affect Your HELOC Monthly Payment?

Several variables move your payment up or down:

• Outstanding balance – a higher drawn amount raises both interest-only and amortized payments.
• APR fluctuations – variable rates shift with market indexes such as the prime rate.
• Draw period length – a longer draw period delays principal repayment but does not eliminate it.
• Repayment term – a shorter term increases the monthly minimum but cuts total interest paid.
• Extra principal payments – paying principal during the draw period shrinks the balance that eventually amortizes.

For additional consumer guidance on home equity products, visit the Consumer Financial Protection Bureau.