HELOC Calculator
Home equity line planning model
Model the draw period, repayment reset, rates, and equity
Result
Calculation summary
Enter values to see the result
Live HELOC preview
Payment transition from draw to repayment
- Balance entering repayment
- $50,000.00
- Payment change at reset
- +$79.74
How to use this calculator
- 1Enter the home value, first-mortgage balance, HELOC limit, current balance, and any immediate additional draw.
- 2Enter the remaining draw period, draw-period rate, optional monthly principal payment, repayment term, and modeled repayment-period rate.
- 3Add closing costs, annual fees, and a planning CLTV guideline, then review the payment transition, rate stress test, equity ratios, and month-by-month schedule.
Formula
Repayment payment = P × r ÷ (1 − (1 + r)^−n)
P is the modeled balance when the draw period ends, r is the assumed monthly repayment rate, and n is the number of repayment months. Draw-period interest is calculated monthly on the outstanding balance.
Calculation steps
- Add the planned immediate draw to the current HELOC balance and verify that the result stays within the entered credit limit.
- During each remaining draw month, calculate interest on the opening balance and subtract the optional fixed principal payment.
- Amortize the draw-end balance across the selected repayment term at the modeled repayment-period rate.
- Compare the last draw-period payment with the first scheduled repayment payment to measure the payment change.
- Recalculate the repayment payment and interest at the base rate and at rates one, two, and three percentage points higher.
- Calculate current, post-draw, and full-limit CLTV and compare the entered credit limit with the user-selected planning guideline.
- Add modeled interest, annual account fees, and upfront closing costs to estimate total borrowing cost.
Worked example
A 50,000 balance at 8.5% with 10 draw years and 20 repayment years has an interest-only draw payment based on the outstanding balance. At the end of the draw period, the same balance is amortized into principal-and-interest payments, and higher-rate scenarios show how that payment could change.
Assumptions
- The planned additional draw occurs immediately; no later draws, repayments beyond the entered draw principal amount, redraws, or transaction timing changes are modeled.
- The draw-period rate and repayment-period rate remain constant within their respective scenarios even though actual HELOC rates may change over time.
- The entered monthly draw principal is paid in addition to monthly interest and stops when the balance reaches zero.
- Repayment uses level monthly principal-and-interest payments with no balloon payment unless the lender’s actual terms differ.
- Annual fees are counted once for each started account year across the modeled draw and repayment terms; upfront costs are added to total cost but not financed.
- CLTV is a planning ratio based only on the entered home value, first mortgage, and HELOC. It does not determine eligibility, credit limit, property value, or lender approval.
- Taxes, interest deductibility, rate caps and floors, index reset timing, minimum draw rules, fixed-rate conversions, early-closure fees, and lender-specific payment rules are excluded.
Sources
Frequently asked questions
Why can the payment change when the draw period ends?
Many HELOC structures allow low or interest-only payments during the draw period. The repayment period can require principal and interest over a shorter remaining term, so the scheduled payment may rise.
Does the rate stress test predict future rates?
No. It holds the draw assumptions constant and shows repayment results at the entered rate and at rates one, two, and three percentage points higher.
What does CLTV mean?
Combined loan-to-value divides the first mortgage plus the HELOC balance or limit by the entered home value. The selected maximum is a personal planning guideline, not a lender rule or approval threshold.
How is principal paid during the draw period handled?
The entered amount is applied every month after interest is calculated, limited to the outstanding balance. Paying principal can reduce the balance and later repayment payment, but future redraws are not modeled.
Can I model a HELOC already entering repayment?
Yes. Set the remaining draw years and months to zero. The tool will amortize the entered balance immediately over the selected repayment term.
Does this match my lender statement exactly?
Not necessarily. Actual plans may use different indexes, margins, rate caps, minimum payments, daily interest, transaction dates, fees, fixed-rate segments, or balloon terms. Use the agreement and lender disclosures for exact figures.
Are my home value and debt balances included in a shared link?
No. Financial inputs stay in the browser and the shared link uses the canonical calculator URL plus a result summary.