How it works

Each month interest is charged on the balance that's left, and your payment covers that interest first — only what's left over reduces the principal. That's why a small payment on a high-APR card barely moves the balance.

The payoff time solves the amortization formula for the number of months: n = −log(1 − B×i / M) / log(1 + i), where B is the balance, i the monthly rate and M your payment. If the payment doesn't even cover one month's interest, the balance never clears — the tool flags this as “Never.”

Worked example

A $6,000 balance at 21.9% APR paid at $250/month clears in about 2 years 8 months, and costs roughly $1,970 in interest along the way. Raising the payment shortens both dramatically.

Frequently asked questions

Why does it say 'Never'?
If your monthly payment is less than or equal to the monthly interest, the balance grows or stalls and can never be paid off. Increase the payment to see a real payoff date.

Is APR the same as the monthly rate?
No — APR is annual. The tool converts it to a monthly rate (APR ÷ 12) internally.

Does paying extra help?
Hugely. Any amount above the interest goes straight to principal, cutting both the time and the total interest. Try nudging the payment up.