- Projected total interest
- $131,029
- Modeled available credit
- $450,000
30-Year First-Lien HELOC Calculator
Use your own cash flow to see what the mortgage could do.
Generic payoff claims are not enough. Change the numbers yourself and see how the modeled payoff time, total interest, and available credit respond.
Interactive comparison
How could a first-lien HELOC change your payoff timeline?
Start with your current or planned mortgage balance, enter an illustrative fixed rate and HELOC rate, then add your monthly take-home income and normal non-mortgage spending.
Educational cash-flow model
Results update automaticallyFirst-lien HELOC vs. a standard 30-year fixed mortgage
Income modeled as$7,500 twice monthly
Monthly cash-flow surplus$6,000
Balance after first deposit$442,500
Approx. HELOC daily interest$83.22 → $81.83
Projected results
How could this change the payoff timeline?
Your modeled monthly surplus is $6,000, a substantial share of take-home income.
- Projected total interest
- $600,729
- Available credit
- $0
Modeled difference vs. the scheduled 30-year fixed mortgage$469,700 less interest
Modeled payoff differenceAbout 21 years 11 months sooner
Ready to replace assumptions with current lender terms?Send a short scenario. Chris and the Edge Home Finance, LLC team can check nationwide program availability and connect you with the appropriately licensed loan officer for the property state.
Model assumptions and important limitations
HELOC cash flow: Monthly take-home income is modeled as two equal deposits on the 1st and 15th. Non-mortgage expenses are spread evenly across each month.
Daily interest: The model uses each day’s closing balance and a 365-day year. Actual transaction timing, statement cycles, posting rules, and leap years may differ.
Rates: Both entered rates are illustrations, not quotes. The model holds each rate constant; an actual HELOC rate can rise or fall over time.
Credit limit: For simplicity, the modeled HELOC line starts equal to the entered balance, remains level for 120 months, and then reduces monthly over the remaining 240 months. Available credit is debt secured by the home—not savings or guaranteed access.
Comparison mortgage: Uses standard monthly amortization over 30 years with scheduled principal-and-interest payments and no extra payments.
Not included: Closing costs, lender fees, taxes, insurance, transaction fees, future redraws, income changes, missed deposits, or tax consequences.
Purpose: Educational illustration only—not an offer, approval, commitment, rate quote, financial advice, or guarantee. Actual results and qualification vary.
Expense input: Exclude the mortgage principal-and-interest payment being replaced. Include ordinary spending and any taxes or insurance paid outside the line.
How to read the result
The most important input is not the mortgage rate. It is the cash flow left after normal life.
The model treats monthly income as two deposits and spreads normal non-mortgage spending across the month. That lets the HELOC balance move down when income arrives and back up as expenses occur.
The long-term payoff is driven by the portion of income that ultimately remains after spending. The daily-balance effect can improve interest efficiency while money remains against the line, but it does not create surplus.
Before you decide
Stress-test the result instead of falling in love with the first number.
If the result still looks compelling, the strategy may be more resilient than a model that only works at one assumed rate.
See how sensitive the payoff is to variable-rate risk before treating the projection as meaningful.
A future child, car payment, tuition bill, or lifestyle change can reduce surplus and move the payoff date later.
Use a conservative number if commissions, bonuses, or business income are inconsistent.