Assumptions this tool makes. The minimum payment is 2% of the outstanding balance with a floor of $25, which is a common formulation among issuers and not a term of any particular account; what is entered in the extra field is added to it each month, and the plan rows in the table compare that with the minimum alone and with two fixed-percentage plans. Interest is charged monthly on the balance outstanding at the start of the month, and the balance is reduced by whatever is paid; no new spending is added, no fee is charged, and no promotional or penalty rate is applied. What the calculator reports is interest paid to the issuer, and it says nothing about the deposit side of the comparison — the rates in the text above come from published national averages and the calculator does not compound a deposit. The savings rate used in the comparison is a national average rather than the best available rate, and it is before tax, so a depositor in a higher bracket keeps less of the $18.53 than the page states. Nothing here models a balance transfer, a hardship programme, a settlement offer, or a debt-management plan, and none of those is recommended or evaluated.