b2KIT

Debt Payoff Calculator

Create debt payoff plans using snowball or avalanche methods with timeline visualization, interest savings, and extra payment modeling.

Tested tool guide Tested browser tools Checked August 16, 2026

What Debt Payoff Calculator does, with a checked example

A payoff plan depends on where each available dollar goes after required payments are covered. Enter every balance, APR, and monthly payment, choose snowball or avalanche ordering, and add any amount you can pay above those entries. The calculator projects the payoff sequence, timeline, and interest, making method and extra-payment comparisons visible. The easy mistake is counting the same extra money inside a debt's payment and again in the extra-payment field. Because these are sensitive financial details, the calculation stays in the browser and nothing is uploaded.

Worked example

A concrete input and expected output from the current implementation.

Input

Debt: Promo card; balance: $100.00; APR: 0%; monthly payment: $60.00; extra payment: $0; method: snowball

Expected output

Payoff time: 2 months; total interest: $0.00; total paid: $100.00; payments: $60.00, then $40.00.

At 0% APR, no interest is added. The first payment leaves $40.00, so the final payment is $40.00; avalanche produces the same result when there is only one debt.

How the result is produced

1

Target ordering

Snowball directs the available extra amount to the debt with the smallest balance. Avalanche directs it to the debt with the highest APR. Other debts continue receiving their entered monthly payments. After a target is cleared, its payment is rolled into the amount directed at the next target, preserving the planned monthly outlay until every listed debt reaches zero.

2

Payoff projection

The timeline advances debt balances month by month, accounting for interest and payments, and limits the final payment to the amount still owed. From that schedule, the calculator totals interest and identifies the payoff month. Re-running the same debts with another method or extra amount provides a comparable scenario when the other entries remain unchanged.

Good uses

  • Choosing between smallest-balance momentum and highest-APR interest reduction for several credit cards.
  • Testing how an additional $100 per month changes the final payoff month and total interest.
  • Building a payoff sequence for credit cards, personal loans, and promotional-rate balances.

Limits and checks

  • The projected payoff date is not a lender payoff quote; interest timing and payment posting can produce different statement balances.
  • Future purchases, fees, missed payments, and variable APR changes are not represented unless the inputs are updated.
  • Interest savings are comparable only when scenarios use the same debts and total monthly budget; changing both can obscure the method's effect.

Common questions

Why do snowball and avalanche show the same result?

With one debt, both methods have the same target. Results can also match when the smallest-balance order is already the highest-APR order, or when the budget clears multiple debts in the same month. No, avalanche is not guaranteed to produce a visibly different payoff date or interest total.

Will the projected payoff date match my lender's statement?

Not necessarily. The result is a planning estimate based on the balances, APRs, and payments entered. A lender may accrue interest daily, change a variable rate or minimum payment, add fees, and post payments on particular dates. Use a lender-issued payoff quote when an exact settlement amount is required.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

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