Two questions, one calculator
Find the payment: enter the loan amount, rate and term to get the fixed monthly payment.
Find the payoff time: enter the amount you can pay each month, and the calculator tells you how many payments it takes, the date you'd be done, and the total interest. It's useful for credit cards and personal loans where you choose how much to pay.
When a payment never pays off a loan
Your payment has to be larger than the first month's interest, or the balance never shrinks. The calculator warns you if that happens and tells you the minimum needed to make progress.
Example
A $25,000 loan at 7% over 5 years has a payment of $495.03. Paying a round $500 a month instead clears it in 60 payments, with a smaller final payment.
Frequently asked questions
How is the number of payments calculated?
It uses n = −ln(1 − P·r / M) ÷ ln(1 + r), where P is the loan, r the monthly rate and M the payment, rounded up to whole payments.
Can I use this for a credit card?
Yes. Enter your balance and APR, choose “Time to pay off,” and enter a fixed monthly payment. It assumes no new charges.