HELOC Payment Calculator
The jump from an interest-only draw payment to a fully-amortizing repayment payment catches many borrowers off guard. See both, side by side, before you draw.
Your payment, both phases
Interest-only draw vs. paying principal from the start
Paying principal during the draw costs more early but removes the payment shock and cuts lifetime interest.
| A | B | Difference |
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Where you stand at 1 / 3 / 5 / 10 years
For the path you selected. During an interest-only draw the balance doesn't move — only interest accrues.
Balance over time
Both paths overlaid. Toggle dollars or percent of the original draw, and the time range.
Full amortization schedule
Payment by payment. The interest-only draw rows carry no principal; the first repayment row is highlighted.
| Mo. | Phase | Payment | Interest | Principal | Balance |
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How to read this
A HELOC has two phases. During the draw period most lenders only require interest — cheap, but your balance never falls. When the draw ends, the repayment period amortizes that full balance over a shorter term, so the payment jumps. That jump is the payment shock, and it's the number to plan around — not the comfortable draw payment.
The comparison shows the alternative: paying principal during the draw. It costs more each month up front, but it removes the shock and lowers total interest. Neither is "right" — it depends on your cash flow. We show both honestly, signed, so the trade-off is visible.
Inputs explained
- Amount you'll draw — the balance the payments are based on.
- HELOC rate — variable, set as prime plus your margin; it moves with the Fed, so your real payment will drift.
- Draw / repayment periods — the interest-only years, then the amortizing years.
- Draw-period payments — interest-only (typical) or amortizing from the start.
Educational estimates only — HelocPilot is not a lender and does not provide individualized advice. HELOC rates are variable and your actual payment will change as prime moves. Confirm all figures with your lender.
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Email me these results — and tell me when rates change the math.
- Independent
- Numbers-first
- Sources cited
- No lender ownership
Estimates only — for general information, not individualized financial advice. Actual rates, payments, and terms depend on your lender and circumstances.