Model home equity line draw-period interest and repayment costs.
Overview
A HELOC combines revolving credit flexibility with home-secured borrowing. During draw periods, many borrowers pay interest-only amounts that can rise if rates increase.
This calculator helps you estimate payment behavior in both draw and repayment phases, including potential payment shock when principal repayment begins.
Because HELOCs are often variable-rate products, run multiple rate scenarios and confirm terms from your lender disclosures before borrowing.
Steps
Input average or planned outstanding HELOC balance.
Define draw years and interest-only assumptions.
Use current index-plus-margin expectation.
Enter years available for principal amortization.
Review draw payment and post-draw payment estimates.
Model possible increases in variable borrowing cost.
Math
Draw payment often ~ Balance x periodic rate; repayment uses amortization PMT formula
During draw, payments may cover only interest on outstanding balance. During repayment, the remaining principal is amortized over the repayment term at the applicable rate.
Worked cases
Monthly interest ≈ 80,000 x 0.08 / 12
Draw-period payment is about $533 if interest-only.
Amortize principal over repayment term at current rate
Payment rises materially versus draw-period interest-only payment.
Recompute draw and repayment payments
Higher variable rates significantly increase monthly cash requirement.
Why use this
Questions