Debt 1 balance ($)

Debt 1 min payment ($)

Debt 1 APR (%)

Debt 2 balance ($)

Debt 2 min payment ($)

Debt 2 APR (%)

Debt 3 balance ($)

Debt 3 min payment ($)

Debt 3 APR (%)

Extra payment ($)

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Every figure above is calculated locally in your browser from the assumptions shown. No inputs are sent anywhere. See the methodology section below for how this tool works.

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Card balance shrinking month by month under the debt snowball — The card falls from $1,000 to zero in 8 months.

Method & verification

How This Tool Works

fact-checked against our calculation methodology

Calculation Method

Debt Snowball Calculator computes Payoff from Debt 1 balance, Debt 1 min payment, Debt 1 APR, Debt 2 balance, Debt 2 min payment, Debt 2 APR, Debt 3 balance, Debt 3 min payment, Debt 3 APR and Extra payment.

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BoringToolsKit methodology and verification standard

No unrelated authority link is added merely to make this page look sourced. Tool-specific external sources are shown only when they directly support the method, rate, or rule.

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Worked example: $100 extra, two debts, month by month

Take a $1,000 card at 24% APR with a $40 minimum and a $2,000 loan at 10% APR with a $60 minimum, plus $100 of extra cash. The calculator sorts by balance, so the card is first. The monthly pool is $100 extra plus the smallest debt's minimum, $140 total. In month 1 the card accrues $1,000 x 24% / 12 = $20.00 interest, pushing it to $1,020.00; the $140 payment brings it back to $880.00. The loan accrues $2,000 x 10% / 12 = $16.67 and, with nothing left over, grows to $2,016.67. Combined interest that month: $36.67.

Month 2 runs the same way: the card accrues $880.00 x 2% = $17.60, hits $897.60, and the $140 payment drops it to $757.60. The card's interest charge keeps shrinking ($15.15 in month 3, $10.11 in month 5) because every payment shrinks the base it is charged on. In month 8 the card's remaining $107.89 plus $2.16 interest is fully cleared by the $140 pool, and the leftover $29.96 rolls onto the loan. From month 9 the whole $140 plus the loan's own $60 minimum, $200 total, hits the loan each month. With these inputs the run ends in 23 months at roughly $362 total interest.

What the calculation leaves out

The payment pool is smaller than real snowball budgets. It counts your extra amount plus one minimum: the smallest debt's. In the example above the pool is $140, but a real household would also keep paying the $60 minimum on the loan, a $200 monthly outlay. Because those other minimums are not modeled, the tool's payoff timeline is slower than what you would actually live through, and its interest figure is a shade high. Treat both numbers as conservative.

Minimums are also static. The $40 stays $40 for all 23 months, while card issuers typically set minimums as a percentage of balance, so real minimums fall as you pay down. On the accrual side, interest is charged at the start of each month on the pre-payment balance, which slightly overstates interest versus daily-balance billing. Finally, the loop hard-stops at 600 months: if your extra amount is near zero and interest outgrows your payments on any debt, the balance never reaches zero, and the tool silently caps the run rather than showing a permanent treadmill. If the result lands anywhere near that cap, raise the extra amount until the timeline turns finite.