How the payoff math works
This calculator uses the standard amortization formula for a fixed monthly payment. On a $10,000 balance at 20% APR with a $300 monthly payment, you would be debt-free in about 50 months and pay roughly $5,000 in interest.
Interest accrues monthly on the remaining balance. Each month a slice of your payment covers the newly charged interest and the rest reduces principal. As the balance falls, the interest charge shrinks, so a growing share of each payment goes to principal.
The result assumes the APR and your payment stay constant every month. If your rate changes, you miss a payment, or you add new charges, the real timeline will differ from the estimate.
Every extra dollar cuts months and interest
The relationship between payment size and total cost is not linear. Raising your payment shrinks the principal faster, and a smaller principal accrues less interest each month, so the savings compound over the life of the payoff.
Compare these payment levels on a $10,000 balance at 20% APR.
Going from $300 to $400 a month saves 17 months and about $1,800 in interest. That is why the extra payment field matters: a modest bump in your monthly payment can be the difference between years and months.
| Monthly payment | Months to payoff | Total interest |
|---|---|---|
| $300 | 50 months | $5,000 |
| $400 | 33 months | $3,200 |
| $500 | 25 months | $2,500 |
| $600 | 20 months | $2,000 |
Minimum payments can trap you for decades
Most cards set the minimum payment as a small percentage of the balance, plus interest. When the minimum sits close to the monthly interest charge, almost nothing goes to principal and the balance crawls downward.
If your payment is lower than the monthly interest, the balance actually grows every month. In that case the formula returns no finite payoff date, and this calculator caps the projection at 20 years so you can see how little progress a too-small payment makes.
Budgeting the full payment you can afford each month, not just the minimum, is the single most effective lever for getting out of credit card debt.
Frequently Asked Questions
How is credit card payoff calculator calculated?
The formula is: n = -ln(1 - (r x P) / M) / ln(1 + r), where r is the monthly rate, P is the balance, and M is the monthly payment. Enter your values above and click Calculate to see your personalized result instantly. This calculator finds how many monthly payments it takes to clear a credit card balance at a fixed APR. For a $10,000 balance at 20% APR with $300 monthly payments, you would be debt-free in about…
What inputs do I need for the credit card payoff calculator?
You need: Balance, Apr, Monthly Payment, Extra Payment. Default values are pre-filled — adjust them to match your personal finances for a customized result.
Is the credit card payoff calculator free to use?
Yes — all TorchFI calculators are completely free. No registration, no email required. Calculations run entirely in your browser for maximum privacy. We never see or store your financial data.
How does the credit card payoff calculator help with FIRE planning?
See how long it takes to pay off a credit card balance and the interest you will pay. Add an extra monthly payment to see how much sooner you can be debt-free. This calculator helps you make data-driven decisions about your financial independence journey instead of relying on guesswork.