Calculator Inputs
Example Data Table
| Scenario | Balance | APR | Method | Estimated Minimum | Interest Portion |
|---|---|---|---|---|---|
| Draw phase, interest-only | $50,000 | 9.25% | Interest-only | $385 | $385 |
| 1% of balance rule | $50,000 | 9.25% | % of balance | $500 | $385 |
| Fixed minimum, interest protected | $20,000 | 8.00% | Fixed ($250) | $250 | $133 |
| Repayment, amortizing 15 years | $50,000 | 9.25% | Amortizing | $513 | $385 |
Formula Used
- Monthly rate: r = (APR ÷ 100) ÷ 12
- Interest-only minimum: Interest = Balance × r
- Percent-of-balance minimum: Payment = Balance × (Percent ÷ 100) (then optionally enforce interest coverage)
- Amortizing payment: PMT = P × r ÷ (1 − (1 + r)−n), where n = Years × 12
- Greater-of rule: Minimum = max(selected rule amounts)
- Principal portion: Principal = max(Minimum − Interest − Fees, 0)
- End balance: End = max(Begin − Principal, 0)
How to Use This Calculator
- Enter your current HELOC balance from your latest statement.
- Choose APR, or select Index + Margin for variable-rate lines.
- Add optional rate floor/cap if your agreement specifies them.
- Select the minimum payment method that matches your lender.
- Set percent, fixed minimum, and repayment term as needed.
- Include any monthly service fee and an optional payment floor.
- Keep “Ensure covers interest” checked to prevent negative amortization.
- Click “Calculate” to view results above the form, then download CSV/PDF.
Payment rules lenders commonly use
HELOC statements usually compute a minimum payment using one rule or the greater of several rules. Common methods include interest-only, a fixed dollar minimum, a percentage of outstanding balance, or a fully amortizing payment over the repayment term. This calculator lets you match those rules and see how the due amount changes as balance declines.
Interest, fees, and principal breakdown
Monthly interest is estimated from the APR divided by twelve, then multiplied by the current balance. If your lender charges a monthly maintenance fee, it is added to the minimum due. Any payment above interest and fees is treated as principal reduction. When the “ensure interest coverage” option is enabled, the minimum cannot fall below interest plus fees, helping you avoid negative amortization.
Example numbers for planning
At a $50,000 balance and 9.25% APR, interest-only is about $385 for the first month. If your lender requires 1% of balance, the minimum becomes $500, with the extra amount reducing principal. An amortizing 15-year payment at the same rate is roughly $513, accelerating payoff compared with interest-only during the draw period.
Projection insights you can use
The projection table recomputes interest each month using the updated balance and your chosen rule. This reveals how a percentage-of-balance minimum can keep payments steadier early, while amortizing payments maintain a repayment schedule. The chart visualizes month-by-month balance and payment so you can compare affordability across rule settings. To test sensitivity, change the APR by one point and observe how minimum due and payoff speed shift materially overall.
Using results responsibly
Actual HELOC billing may use daily accrual, statement-cycle timing, recent draws, and promotional rates. Treat results as planning estimates, then reconcile with your statement. If you are choosing a payment strategy, compare the minimum to a higher “target payment” that reduces principal faster and lowers total interest over time. Small extra payments can shorten payoff and stabilize cash flow.
FAQs
Does the minimum payment always reduce my balance?
Not always. If your minimum equals interest plus fees, principal may be zero and your balance won’t drop unless you pay extra. If the minimum is less than interest, unpaid interest can add to the balance, depending on lender rules.
What does “Greater-of” mean?
Some lenders set the minimum as the largest of multiple calculations, such as interest-only, a fixed dollar amount, or a percent of balance. Select “Greater-of” and check the rules your agreement lists to replicate that approach.
How do floors and caps affect the result?
When you use Index + Margin, the calculated APR can be restricted by a rate floor or cap. The calculator applies those limits before converting APR to a monthly rate, changing the interest portion and the required minimum payment.
Why is the projection limited to no new draws?
To isolate payment behavior, the projection assumes you do not borrow additional funds. New draws increase balance and interest, and can change lender minimum rules. Use your current balance for “as of today” planning, then rerun after any draw.
Is the amortizing option the same as a loan payment?
It uses a standard amortization payment formula based on your balance, APR, and term. Many HELOCs switch to an amortizing schedule in the repayment period, but statement timing and variable rates can cause real payments to differ slightly.
Can I download my results?
Yes. After you calculate, use the Download CSV or Download PDF buttons. Downloads include your inputs, summary amounts, and the projection table so you can share results or keep them with your budget notes.
Important Notes
This tool estimates minimum payments using typical lender rules. Real statements may include timing differences, daily interest accrual, promotional rates, taxes, or transaction activity. Always confirm with your lender’s statement.