Methodology
The calculator builds a dated repayment ledger, applies simple daily interest between payment events, and then applies scheduled, extra, and one-time payments in sequence. Fixed-payment and changing-minimum modes project the balance forward, while target-date mode iteratively estimates the starting recurring payment needed to reach the selected date.
Assumptions
- The entered balance, APR, payment timing, promotional rate, extra payments, and annual increases remain as entered unless the user changes them.
- Interest is estimated with a simplified daily-interest model and payment events occur on the dates generated by the selected schedule.
- Changing-minimum mode uses the selected simplified formula and minimum floor rather than a specific issuer's complete statement rules.
- Currency selection changes number formatting only and does not convert amounts.
Limitations
- Actual issuers may use average daily balances, different compounding conventions, statement timing, minimum-payment formulas, grace periods, and rounding rules.
- The model does not automatically include new purchases, late fees, annual fees, penalty APR, balance-transfer fees, cash-advance rules, or currency conversion.
- Target-date results are planning estimates and may not match a future card statement or issuer payoff quote exactly.
- The output is educational information and not financial, credit, legal, or tax advice.
Choose the payoff question first
Use Fixed payment when you know the recurring amount you can send, Changing minimum when you want to model an estimated statement minimum, or Target payoff date when you want to solve for the starting payment needed to pursue a deadline.
Add the details that change the plan
The calculator can include weekly, biweekly, or monthly payments; recurring extras; a one-time lump sum; annual payment increases; and a promotional APR period. Compare the resulting payoff time, total interest, scheduled-payment pattern, and balance milestones before deciding which plan is sustainable.
Use the result as a planning scenario
A lower projected interest total is only useful when the payment can be maintained. Compare the result with your monthly budget, preserve essential cash flow, and confirm the issuer’s actual minimum payment and payoff information before acting.
Privacy and saved settings
The calculator does not require an account or bank connection. Calculator inputs and saved settings remain in this browser. General page-level analytics may record that a page was visited, but they must not receive balances, APRs, payment amounts, dates, or other calculator inputs.
