Buying & selling
HELOC Payment Calculator
Compare the interest-only draw period with repayment, extra principal, an additional initial draw and annual fees.
Calculate your result
What this calculator estimates
Estimate interest-only and amortizing HELOC payments. It combines the inputs below to produce Interest-only monthly payment. Every assumption remains editable so the estimate can reflect the property, financing and location being evaluated.
Worked example
Using the displayed sample assumptions, the calculator produces $333. This is an illustration, not a market quote. Change one input at a time to understand what drives the result.
Inputs and assumptions
- Current drawn HELOC balance — sample input: 50000 currency units
- Additional draw at start — optional — sample input: 0 currency units
- Annual interest rate — sample input: 8 %
- Interest-only draw period remaining — sample input: 5 years
- Repayment period after draw ends — sample input: 15 years
- Extra monthly principal during draw period — optional — sample input: 0 currency units
- Annual account fee — optional — sample input: 0 currency units
How to interpret the result
Include immediate work and transaction costs in the decision. Compare a conservative case with an expected case and keep a record of the assumptions used.
Common mistake to avoid
Do not confuse purchase price with total cash required. Local definitions, taxes, lending practices and measurement requirements can materially change the result.
Calculation details
Interest uses annual rate ÷ 12. During the draw period, entered extra principal reduces the balance each month. Repayment then amortizes the remaining debt. Rates remain constant and future redraws are excluded.
Results included
- Initial monthly interest-only payment
- Initial principal balance
- Initial monthly payment including extra principal
- Principal repaid during draw period
- Balance at repayment start
- Interest during draw period
- Monthly repayment after draw period
- Interest during repayment period
- Total interest
- Account fees over both periods
- Total financing cost
- Annual equivalent
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Reviewed 2026-09-08.