| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Credit Card A | $3,500 | 24.99% | $120 |
| Credit Card B | $1,200 | 18.50% | $60 |
| Personal Loan | $8,000 | 11.25% | $210 |
- Monthly interest: I = B × (APR/100) ÷ 12
- Balance with interest: B' = B + I
- Total monthly budget: Budget = Σ(minimums) + extra
- Payments: pay all minimums, then apply remaining budget to the highest APR balance.
- Rollover: when a debt is paid off, its minimum payment stays inside the budget for the next debt.
- Enter each debt line: balance, APR, and required minimum payment.
- Add a monthly extra payment amount you can maintain.
- Click Calculate to see months, interest, and payoff date.
- Review the schedule to understand month-by-month changes.
- Use CSV for spreadsheets and PDF for sharing or printing.
Why avalanche prioritization reduces total cost
The avalanche method targets the highest APR first, so expensive interest stops sooner. With a fixed monthly budget, shifting surplus to the top-rate balance typically lowers total interest versus equal-pay ordering. For example, moving $150 of surplus from an 11% loan to a 25% card saves roughly $17 per year per $1,000 of principal, before compounding effects.
How monthly interest is applied in the schedule
Each month adds interest using I = B × (APR/100) ÷ 12, then payments reduce the updated balance. The schedule shows a total interest line plus per-debt interest, so you can spot where costs concentrate. If your statement uses daily interest, treat this as an estimate and keep a small buffer.
Rollover payments and stable cash outflow
This calculator keeps your total outflow stable: minimums plus extra. When one debt reaches $0, its former minimum is automatically reused, increasing the next target payment without raising your budget. That rollover accelerates later months, which is why the plan often feels slow early and faster near the end.
Interpreting payoff time and payoff date
Payoff time is the number of monthly cycles required until all balances reach zero. Payoff date is the month label tied to your start date; it helps align the plan with statements and due dates. If a debt has a minimum below accrued interest, increase your extra payment to avoid negative amortization.
What the balance trend chart tells you
The Plotly chart plots remaining total balance by month. A steeper decline indicates more principal reduction. Early months may drop slower when interest is high, but the slope usually improves after top-rate debts are cleared. If the curve flattens for many months, your monthly budget may be too close to the combined minimums.
Using exports to track progress and adjust
CSV is best for filtering, pivoting, and adding real payments, including one-time bonuses. PDF works for sharing a commitment plan with a partner or counselor. Recalculate after rate changes, promotional expirations, or refinancing offers. Even a 2% APR drop on a $5,000 balance can cut meaningful interest over a year. Record actual payments monthly, then compare variance; small overpayments early usually shorten payoff by several weeks for you.
Does the avalanche method always beat the snowball method?
Avalanche usually minimizes interest because it targets the highest APR first. Snowball can improve motivation by scoring quick wins. The best plan is the one you can follow consistently.
What if my minimum payments change over time?
This plan assumes fixed minimums. If your lender recalculates minimums, update the inputs and run the calculator again. Keeping your total monthly budget steady still preserves the rollover benefit.
How do promotional 0% rates affect the strategy?
Enter the current APR for the promotional period. When the promotion ends, rerun the plan with the new APR. Many people prioritize debts that will jump to a high rate soon.
Why can the first months feel slow?
High interest absorbs part of your payment early, so principal falls gradually. As high-rate balances shrink, interest drops and more of your budget hits principal, making later months accelerate.
Can I include one-time lump-sum payments?
The monthly schedule assumes a repeating budget. Use the CSV to add a lump-sum payment in a chosen month, or temporarily increase the extra payment and recalculate to see the new payoff date.
How accurate is the payoff date?
It is an estimate based on monthly compounding and a constant budget. Real statements may use daily interest, fees, or changing minimums. Use it for planning, then refine with actual statement numbers.