Home Equity Line of Credit Monthly Payment Calculator

This calculator estimates a fixed-rate, fully amortizing monthly payment from a loan amount, annual APR, and repayment term. Enter those three values to see the estimated payment and total interest; an actual home equity line of credit (HELOC) payment can differ because its rate and payment rules may change over time.

Formula

The calculator uses the standard level-payment formula for a fixed-rate installment balance:

Payment = P × r ÷ [1 − (1 + r)⁻ⁿ]

• P is the amount borrowed, in dollars.
• r is the monthly interest rate, calculated as annual APR ÷ 1,200. For an 8% APR, r = 0.08 ÷ 12, or about 0.006667 per month.
• n is the number of monthly payments, calculated as years × 12.

The total-interest estimate is monthly payment × n − P. Payment is rounded to the nearest cent before total interest is calculated, so the total reflects the displayed monthly amount. This calculation assumes the entire balance is borrowed at the start and repaid in equal monthly payments.

Worked Example

Using the calculator’s defaults—$20,000 borrowed, 8% APR, and 5 years:

1. Convert the APR to a monthly rate: 8 ÷ 1,200 = 0.0066667.
2. Convert the term to payments: 5 × 12 = 60 months.
3. Substitute the values: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰].
4. The estimated monthly payment is $405.53.
5. Total paid is $405.53 × 60 = $24,331.80; estimated interest is $24,331.80 − $20,000 = $4,331.80.

Assumptions

• The APR stays fixed for the full term.
• Payments are made monthly, with the first payment one month after borrowing.
• Interest accrues monthly at APR ÷ 12.
• The estimate excludes fees, taxes, insurance, PMI, and escrow. It also does not model additional draws, minimum-payment rules, or a changing rate.

How HELOC Monthly Payments Work

A HELOC is a revolving credit line secured by home equity. Unlike a typical installment loan, it often allows borrowing, repayment, and further borrowing during a draw period, subject to the account’s terms. The amount owed can therefore change as you use the line or make payments. A quoted monthly payment is meaningful only alongside the balance, rate, and applicable payment terms.

Many HELOCs have a draw period followed by a repayment period. During the draw period, a required payment may be calculated differently from a payment that fully pays principal and interest. When repayment begins, the required amount may rise because principal must be repaid over a limited period. The exact structure varies by contract; check the lender’s disclosures for the payment calculation, rate adjustment method, and timing of each phase.

This calculator treats the amount entered as a one-time balance that is immediately repaid over the full term. It is useful for understanding standard amortization arithmetic, not for reproducing every HELOC statement. If you have an interest-only payment, a variable rate, or a changing balance, the result will not represent that payment.

Using the Estimate Carefully

Enter the amount you expect to owe, rather than the total credit line unless you expect to draw it all. Use the APR and term supplied for the specific borrowing and repayment arrangement; do not treat the example defaults as a market quote. If the rate is variable, a single APR gives only a snapshot under the assumption that it never changes.

• Separate the draw from the repayment period. A draw-period payment and a repayment-period payment can be calculated differently. Run this formula only with a term and payment structure that match a fully amortizing balance.
• Account for future borrowing. Additional draws increase the balance and can change required payments. The calculator assumes no new borrowing.
• Check the APR and fees separately. The calculation uses the APR entered as a monthly rate and does not add fees or model how fees are charged.
• Expect small rounding differences. Lenders may use daily interest calculations, different payment dates, or statement-specific rounding. The last payment can also differ from the regular amount.

A common misconception is that every HELOC payment is interest-only or that the payment stays level. Neither assumption is safe without checking the account terms: payment rules can differ by phase, and a variable rate or changing balance can alter the amount due. The lender’s payment schedule and periodic statements are the relevant sources for the actual obligation.

What the Result Does Not Tell You

The estimate does not determine how much credit may be available, whether an application will be approved, or whether a particular payment fits a household budget. It also cannot predict future rate changes, lender fees, late charges, or the timing and amount of future draws. Those are outside the formula and must be obtained from the lender’s documents or account information.

To estimate a different balance, term, or APR, change the inputs and compare the results as arithmetic scenarios. Keep the assumptions visible: a lower payment may simply reflect a longer repayment term, while total interest can increase when repayment takes longer. A variable-rate HELOC may produce a different result if its rate changes, even when the balance and scheduled term remain unchanged.

Frequently Asked Questions

How do I calculate a HELOC monthly payment?
For a fixed-rate balance paid off in equal monthly installments, convert APR to a monthly rate by dividing by 1,200, convert years to months, and use the level-payment formula shown above. A HELOC with different payment rules needs its own terms applied.

Are HELOC payments usually interest-only?
Payment structures vary. Some contracts may calculate payments during a draw period differently from payments during repayment. Read the account disclosures to learn whether principal is due and how the required amount is determined.

Can my HELOC payment change?
It can change if the balance changes, the rate adjusts, or the payment phase or calculation changes. The contract explains which factors apply to a specific line of credit.

Why might my lender’s payment differ from this estimate?
This estimate assumes monthly compounding, a fixed APR, a constant balance, equal payments, and no added fees. A lender may use different timing, daily interest accrual, variable rates, changing draws, or a different repayment schedule.

Does this calculator show the minimum HELOC payment?
No. It estimates a level payment that amortizes the entered balance over the entered term. A minimum payment may follow a different contract formula, so use the lender’s statement or disclosures for that figure.

This result is an estimate for education, and the lender’s disclosure gives the exact figures.

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in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
out pmt | Monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2