How to use the repayment calculator
- Choose how you want to repay: pay a fixed amount each month, or pay off in a set time.
- Enter the balance owed today.
- Enter the interest rate (APR) on the balance.
- Add any flat monthly fee, such as an account or service charge. Leave it at 0 if there is none.
- Enter your monthly payment, or the number of months you want to be done in.
- Read the time to repay or the payment needed, the total interest and fees, and the comparison table.
Unlike a fixed-term loan, a credit line or card lets you choose what to pay. This calculator answers the two questions that matter for that kind of balance: how long will my payment take, and how much do I need to pay to finish on time?
How the repayment is worked out
Each month, interest is added at the APR ÷ 12, then any fee, then your payment comes off:
The fee comes off the top of each payment, so only M − fee works against the balance and its interest. A payment must be more than the first month's interest plus the fee, or the balance never falls. The calculator tells you that minimum.
Worked example
The defaults are a $5,000 balance at 18% APR, no fee, paying $200 a month:
- Monthly rate: 0.18 ÷ 12 = 0.015, so the first month's interest is $75 and $125 reduces the balance
- n = −ln(1 − 75 ÷ 200) ÷ ln(1.015) = 0.470004 ÷ 0.0148886 = 31.57
- That is 31 payments of $200 and a final payment of $113.96: 2 years 8 months
- Total interest: $1,313.96, so you repay $6,313.96 in all
To clear it in 24 months instead, the payment is 5,000 × 0.015 ÷ (1 − 1.015^−24) = $249.62, with $990.89 of interest. A $10 monthly fee on the $200 plan stretches it to 2 years 10 months and adds $340 of fees and about $94 of extra interest.
What paying more does
The same $5,000 at 18% with no fee:
| Monthly payment | Paid off in | Total interest |
|---|---|---|
| $200 | 2 years 8 months | $1,313.96 |
| $225 | 2 years 4 months | $1,127.78 |
| $250 | 2 years | $989.13 |
| $300 | 1 year 8 months | $797.17 |
| $400 | 1 year 2 months | $578.63 |
Doubling the payment from $200 to $400 more than halves both the time and the interest. On a high-rate balance, every extra dollar early on saves the most.
Before you rely on the result
The calculator assumes the rate stays the same and you add nothing new to the balance. Variable-rate credit lines can change rate, and new purchases restart the clock. Credit cards usually work out interest on the average daily balance, which can cost slightly more than this monthly estimate. For a credit card with a minimum payment rule, use the credit card payoff calculator; for several balances at once, the debt payoff calculator orders them for you.
Frequently asked questions
What is the smallest payment that pays off the balance?
Anything more than the first month's interest plus the monthly fee. On $5,000 at 18% with no fee, that is just over $75. A payment that close to the minimum would take decades, so the useful question is how much more than that you can afford.
How is this different from the payment calculator?
The payment calculator is built around a loan with a fixed term. This one is for balances where you decide the payment, such as credit lines and store cards, includes a monthly fee, and shows how other payments or deadlines compare.
Why does a monthly fee matter so much?
Because it comes out of every payment before anything reaches the balance. A $10 fee on a $200 payment means only $190 works on the debt, and you pay the fee every month until you are done. On the default example it adds 2 months and about $434 in total.
Does paying twice a month help?
A little. Interest is charged on the balance, so paying half the amount every two weeks lowers the average balance and trims interest, and 26 half payments add up to an extra month's payment each year. The bigger win is simply paying more.
Related calculators
- Credit Card Payoff Calculator — How long a card balance takes to clear and the interest you pay, at a fixed payment or a target date.
- Debt Payoff Calculator — Compare the snowball and avalanche methods across all your debts and see your debt-free date.
- Payment Calculator — Monthly payment for a loan with a fixed term, or how long a fixed monthly payment takes to clear it.
- Debt Consolidation Calculator — Compare up to four debts with one consolidation loan: monthly payment, total interest, payoff time.
Results are estimates for educational purposes and are not financial, tax or legal advice. See our disclaimer.