Compare the debt snowball, the debt avalanche and paying only minimums: debt-free date, total interest and a month-by-month plan
This calculator's method was checked against the sources below on .
Simulates paying off several debts month by month and compares three plans: snowball (smallest balance first), avalanche (highest APR first) and minimum payments only. Each plan pays every minimum, sends everything left to the target debt, and rolls a cleared debt's payment into the next one.
interest = balance × APR ÷ 12; new balance = balance + interest − payment
balancewhat you owe on that debt at the start of the monthAPRannual percentage rate as a decimalpaymentits minimum plus any extra sent to it that monthYou list your debts from the smallest balance to the largest, ignoring interest rates. You pay the minimum on every debt and put all the extra money on the smallest one. When it is gone, its whole payment is added to the next debt, so the amount you throw at each debt grows like a rolling snowball.
The avalanche (highest APR first) always costs the least interest and is never slower in total time. The snowball clears debts sooner, which some people find motivating. The calculator shows both side by side for your own debts, so you can see exactly what the quick wins cost. If the gap is small, choose the one you will stick with.
Each month it adds interest of balance × APR ÷ 12 to every debt, rounded to the cent, then applies your payments. An advanced option switches to the daily-rate method (balance × APR ÷ 365 × days in the month) that many card issuers use. Rates are assumed to stay fixed.
That balance grows every month and paying only the minimum never clears it. The calculator warns you and shows the minimum-only plan as "never pays off". The snowball and avalanche plans can still clear the debt because they add extra money on top of the minimums.
Extra per month adds a fixed amount to the total of your current minimum payments. A monthly budget is the total you commit to paying. Both keep the total payment the same every month, so when a debt is paid off its old payment automatically moves to the next one.
Because minimums shrink as the balance falls (on percentage-based cards) or leave most of each payment as interest early on. Nothing is rolled over, so no debt gets paid faster. The comparison shows the interest you would save by following either plan.
Many counsellors suggest keeping a small starter cushion first so a car repair does not go back on a card, and then paying debt aggressively. The right amount depends on your income stability, so this is a judgement call, not something a calculator can decide.
They are estimates from the inputs you give, assuming fixed rates and no new charges, fees or promotional rates. Lenders compute interest on slightly different day-counts, so real statements may differ by a few cents per month. This is not financial advice.