HELOC Fixed Payment Payoff CalculatorFree online financial calculator — instant results, no sign-up

r = a / 1200; B₀ = P. For each month t: Iₜ = Bₜ₋₁ × r; Aₜ = min(M, Bₜ₋₁ + Iₜ); Bₜ = Bₜ₋₁ + Iₜ − Aₜ. Continue until Bₙ = 0. Months to payoff = n; total payments T = Σₜ₌₁ⁿ Aₜ; total interest J = T − P. For r > 0 and M > P × r, n = ceil[−ln(1 − P × r / M) / ln(1 + r)]. For r = 0 and M > 0, n = ceil(P / M).

• PStarting HELOC balance in dollars.
• aAnnual interest rate entered as a percentage, such as 8.5.
• rMonthly interest rate expressed as a decimal.
• MPlanned fixed monthly payment in dollars.
• tMonthly payment period, starting at 1.
• BₜRemaining balance after payment in month t; B₀ is the starting balance.
• IₜInterest charged for month t in dollars.
• AₜActual payment for month t, capped at the balance plus that month's interest.
• nNumber of monthly payments needed to repay the balance, including a smaller final payment.
• TTotal of all payments in dollars.
• JTotal interest paid in dollars.
• Σ, ln, ceilΣ means sum across payment periods, ln is the natural logarithm, and ceil rounds up to a whole number.

Convert the annual percentage rate to a monthly decimal rate by dividing by 1,200. Each month, calculate interest on the opening balance, add that interest, and subtract the payment. Reduce the final payment to the amount needed to bring the balance to zero, then total the payment periods and amounts paid. With a $45,000 balance, an 8.5% annual rate, and a $700 monthly payment, the results are 87 months to payoff, $15,260.26 in total interest, and $60,260.26 in total payments. The first 86 payments are $700, followed by a final payment of approximately $60.26.

These are the calculator's starting values and the results it actually produces for them.

1. 1Enter your existing HELOC balance in dollars, using $45,000 to reproduce the default example.
2. 2Enter the annual interest rate you want to assume throughout repayment; the default is 8.5%.
3. 3Enter the fixed monthly payment you plan to make; the default is $700.
4. 4Run the calculation and review months to payoff, total interest, and total payments.
5. 5Adjust the payment to compare repayment plans, keeping the balance and rate unchanged when isolating the effect of payment size.

Further reading

• CFPB