Enter your debts and see exactly how the snowball (smallest balance first) and avalanche (highest interest first) methods compare — time to debt-free and total interest paid, side by side.
Your debts Free
Name
Balance ($)
APR (%)
Min payment ($)
+ Add another debt
Extra monthly payment
This is on top of the minimum payments above. The more you can add here, the faster either method pays off and the bigger the gap between them.
Snowball vs Avalanche
Avalanche is always the mathematically optimal choice or a tie — it targets your highest-interest debt first, so it never pays more total interest than snowball. Snowball targets your smallest balance first instead, which can't beat avalanche on interest, but many people find the quick wins of closing out small accounts keeps them motivated to stick with the plan. Neither is "wrong" — pick the one you'll actually stay consistent with.
Quick answers
Which method should I use?
If you're confident you'll stay disciplined either way, avalanche saves you money. If you've struggled to stick with a debt payoff plan before, snowball's quick wins (paying off a small card completely within a few months) can be worth the extra interest cost for the motivation boost. Some people do a hybrid: snowball on very small balances first, then avalanche for the rest.
What if I miss a payment or the extra amount changes?
This calculator assumes consistent payments every month with no missed payments, rate changes, or new debt added. Real payoff timelines will shift if any of those happen — treat this as a target plan, not a guarantee, and rerun it whenever your situation changes.
Should I pay off debt or invest instead?
A common rule of thumb: if a debt's interest rate is higher than what you'd realistically expect to earn investing (historically averaging support for low-cost index funds is often cited around 7–10% annually before inflation, though returns vary and aren't guaranteed), paying down that debt first is usually the safer, guaranteed "return." For high-interest credit card debt (typically 20%+), paying it off first is almost always the better move.
How to use this planner
The planner simulates your debts month by month, so the inputs need to be as close to the statements as you can get them.
Add each debt with its current balance, its APR, and its minimum payment. Use the minimum printed on the statement, not the amount you usually pay.
Enter the extra you can put toward debt each month. If the answer is zero, that is a valid result and the planner will show you the minimum-only timeline.
Compare the snowball result against the avalanche result. Both pay the same total each month; they differ only in which balance gets the extra.
Read the months-to-debt-free and the total interest, and treat the months figure as the one to plan around.
Leave out any debt you are still charging. A balance that grows each month breaks the simulation's assumption.
A worked example: a store card and a credit card
Two debts. A store card with $1,200 at 8% and a $40 minimum. A credit card with $4,500 at 24% and a $120 minimum. Add $150 of extra payment.
Before comparing strategies, look at what each balance costs per month in interest, which is the balance times the APR divided by 12. The store card costs $8.00 a month. The credit card costs $90.00 a month.
That single pair of numbers explains the whole decision. The store card's $40 minimum pays off $32 of principal every month. The credit card's $120 minimum pays off only $30, because three quarters of the payment is interest. The card is barely moving even though it costs three times as much to hold.
So avalanche sends the extra $150 to the 24% card. Snowball sends it to the smaller balance first, clears the store card quickly, and then rolls its $40 minimum into the card. Both finish, and the avalanche run pays less interest overall; the snowball run gets the satisfaction of closing an account sooner. The gap between them is smaller than the cost of not making the extra payment at all.
What your results mean
Months to debt-free is the headline. Total interest is the price of the order you chose. The difference between the two methods is usually a few hundred dollars on consumer balances, while the difference between paying minimums and paying extra is measured in years.
Freed minimums roll forward in the simulation, which is what makes snowball work: once a balance closes, its minimum joins the extra payment. If you would spend that freed money instead, the timeline will not match your life.
Minimums are held constant. Real card issuers recalculate the minimum as the balance falls, and a promotional 0% rate that expires mid-payoff will change everything. Neither is modeled.
If the tool reports that a debt never pays off, it means the payment does not exceed the monthly interest. That is not a formatting problem. It is the single most important output on the page, and it needs a larger payment or a different plan, not a smaller balance target.
Frequently asked questions
Snowball or avalanche — which is better?
Avalanche costs less in interest because it targets the highest rate. Snowball produces faster wins because it clears small balances first. If the motivational effect is what keeps you paying, snowball finishing is worth more than the interest difference.
What if I can only pay the minimums?
Then the planner shows the true timeline, which is often decades on a high-rate card. That is the case for finding even a small extra amount, or for talking to a nonprofit credit counselor about the balances.
Should I include my mortgage?
Usually not in the same list as revolving debt. A mortgage at a low fixed rate behaves differently and paying it off early is a separate decision. Include it only if it is the debt you are actually attacking.
Does this use my credit score?
No. It uses balances, rates, and payments. Credit utilization and payment history affect your score separately, and neither is modeled here.
Why does the order change the total interest at all?
Because interest accrues on every balance every month. The debt carrying the highest rate adds the most interest per dollar, so retiring it first stops the most expensive accrual soonest.
What about balance transfer offers?
A 0% transfer can help, but the fee is usually a percentage of the balance and the rate resets later. The planner has no transfer-fee field, so subtract the fee from the benefit before assuming the move wins.
Sources & references
Snowball and avalanche are payoff orders, not financial products. The consumer context is the CFPB's.