Model an interest-only draw period followed by amortizing repayment of the entered balance.
The calculator keeps the balance, rate convention, payment timing, fees, and term visible so you can reproduce the result and compare it with an actual offer or statement.
The cash-flow relationship
Place every amount at the correct time
Draw payment = balance × draw rate/12; unchanged principal then amortizes at the entered repayment rate over the repayment period. With zero draw months, the draw-period payment is reported as zero and repayment begins immediately.
Visual explanation
What changes the borrowing result
StartPhase 1Phase 2Final payment / balanceDraw payment = balance × draw rate/12; unchanged principal then amortizes at the entered repayment rate over the repayment period. With zero draw months, the draw-period payment is reported as zero and repayment begins immediately.
Read the result in context
Use the estimate with its contract assumptions
A 12,000 balance at 6% has a 60 interest-only payment; at 0% over a later 12 months, repayment is 1,000 monthly.
The balance is held constant during a positive modeled draw period: no new draws and no principal payments. With zero draw months, the draw-period payment is reported as zero and repayment begins immediately. HELOC rates are often variable; this tool uses only the two rates entered and does not predict future index changes. A real HELOC is secured by the home, so missed repayment can put that home at risk.
Quick guide
How to use this calculator
Enter all amounts in one consistent currency.
Use the rate and whole-period timing named by each visible label.
Read the result together with its phase, fee, security, and contract exclusions.
Calculation method
Calculation method
Draw payment = balance × draw rate/12; unchanged principal then amortizes at the entered repayment rate over the repayment period. With zero draw months, the draw-period payment is reported as zero and repayment begins immediately.
Entered monetary components use exact fixed-decimal arithmetic. Amortizing phases use the reviewed stable loan schedule and round only for presentation.
Worked example
Worked example
A 12,000 balance at 6% has a 60 interest-only payment; at 0% over a later 12 months, repayment is 1,000 monthly.
Draw payment = balance × draw rate/12; unchanged principal then amortizes at the entered repayment rate over the repayment period. With zero draw months, the draw-period payment is reported as zero and repayment begins immediately.
Supported inputs
Precision and limits
Visible input limits
Amounts are capped at 1e12, rates at 1000%, phases at 1,200 months, and fixed decimals at 12 places.
Estimate, not advice
The tools model only entered cash flows and contract components. They do not assess approval, legal enforceability, property value, future variable rates, or refinancing availability.
International scope
No currency, country, lender threshold, secured-credit law, tax treatment, fee rule, or consumer protection is assumed.
Calculator-specific assumptions
The balance is held constant during a positive modeled draw period: no new draws and no principal payments. With zero draw months, the draw-period payment is reported as zero and repayment begins immediately. HELOC rates are often variable; this tool uses only the two rates entered and does not predict future index changes. A real HELOC is secured by the home, so missed repayment can put that home at risk.
