Debt Payoff Calculator (Snowball vs Avalanche)
Enter a few balances, APRs, and minimum payments to estimate your payoff timeline. Compare the debt snowball (smallest balance first) vs avalanche (highest APR first) methods.
Show first 24 months (estimated)
| Month | Payment | Interest | Principal | Remaining |
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How to use this debt payoff calculator
Run 2-3 scenarios: minimums only, a realistic extra payment, and an aggressive extra payment. The differences in payoff date and total interest are usually the motivation you need.
Start by entering each debt’s balance, APR, and required minimum payment. Add an optional extra monthly payment (even $25-$200 can change the timeline). Then choose a strategy:
- Avalanche targets the highest APR first to minimize interest.
- Snowball targets the smallest balance first to create faster “wins.”
Both methods keep paying minimums on all other debts. Once one debt is paid off, its payment rolls into the next target debt. That “rollover” is the entire game.
What the results mean (months, payoff date, interest)
The calculator simulates month-by-month payments. “Months to debt‑free” is how many monthly cycles it takes until every balance reaches $0. The payoff date is the start month plus that many months. Total interest is the sum of interest charges across all debts during the simulation.
Snowball vs avalanche: which should you pick?
If your main goal is to pay the least interest, avalanche is usually best because high APR balances are the most expensive to carry. If your main challenge is consistency, snowball can be easier to stick with because you tend to eliminate a balance sooner and feel the progress.
A practical compromise is to start with snowball until you’re “in motion,” then switch to avalanche once your smallest debts are gone. The calculator makes it easy to compare the cost of that choice.
Common mistakes (and how to avoid them)
Most payoff plans fail because the inputs aren’t realistic. A few quick checks help:
- Minimum payment too low: some cards have minimums that change as the balance falls. This calculator uses fixed minimums for clarity, so re-run it if your minimums change.
- APR wrong: use the purchase APR (not a promotional balance transfer rate) unless you know the promo end date.
- Extra payment double-counted: “extra” is on top of all minimums. If you already included a bigger-than-minimum payment in a row, set extra to $0.
- Ignoring fees: late fees or annual fees can materially change the timeline. If fees are recurring, treat them like additional debt or reduce the extra payment accordingly.
Next steps after you get a baseline
Once you have a baseline timeline, use the tool to answer real decisions: “What if I add $100/month?” “What if I refinance a personal loan?” “What if I pause extra payments for 3 months?” This calculator assumes steady payments, so if your plan changes, just rerun it with updated inputs.
Browse the full library any time at /calculators/.
FAQ
Is the debt avalanche method always cheaper?
Usually, yes, because it prioritizes the highest APR first, which reduces how long you carry the most expensive balance. The exact difference depends on your balances, APR spread, and extra payment.
Why does the snowball method feel faster?
Snowball targets the smallest balance first, so you often eliminate a debt sooner and free up that minimum payment. The math isn’t always cheapest, but the early win can improve follow-through.
Does this calculator assume my minimum payments change over time?
No. It treats each minimum payment as fixed so the plan stays understandable. In real life, some credit card minimums shrink as balances fall, rerun the calculator occasionally to stay accurate.
What if one of my debts has a 0% promotional APR?
If it’s truly 0% for the entire payoff period, it should usually be lower priority than high-APR debt. If the promo ends soon, you’ll want to treat the post-promo APR as the real cost (or plan to pay it off before the end date).
How is monthly interest calculated here?
Each month, the calculator applies APR ÷ 12 to the current balance to estimate interest. That interest is added to the balance, then payments are applied. Actual issuers can differ slightly due to daily compounding and statement timing.