Loan Payoff Calculator
Find how long to pay off a loan at a fixed payment.
Results update as you type.
How it works
If you make a fixed monthly payment on a loan, how long until it is gone and how much interest will you pay? This calculator answers both. You enter the loan balance, the annual interest rate, and your monthly payment, and it returns the number of months to pay off the loan and the total interest paid along the way. The math comes from the amortization formula solved for time. The key requirement is that your payment must be larger than the monthly interest on the balance; otherwise the balance never shrinks and the loan is never repaid, which the calculator flags. This tool is especially useful for credit card and personal debt, where you choose your own payment: it shows how a higher payment dramatically shortens the payoff time and slashes total interest, because more of each payment attacks the principal. For example, doubling your monthly payment usually cuts the payoff time by far more than half and saves a large amount of interest. Seeing the total interest is often eye-opening, revealing how much a long, low-payment schedule really costs. Use it to plan how quickly you can become debt-free and to decide how much to pay each month. It assumes a fixed payment and rate; variable rates or changing payments would alter the result. Enter your balance, rate, and payment to compute the payoff time.
Months = −ln(1 − balance × r / payment) / ln(1 + r)
The number of months to pay off a loan is derived from the amortization formula solved for time: the negative natural logarithm of one minus the balance times the monthly rate divided by the payment, divided by the natural logarithm of one plus the monthly rate. If the payment does not exceed the monthly interest, the loan never pays off.
Source:Loan amortization
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter loan balance, interest rate and monthly payment.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Months to pay off updates instantly as you type — no button to press.
Frequently asked questions
How long will it take to pay off my loan?
It depends on your balance, interest rate, and monthly payment. The calculator uses the amortization formula to find the exact number of months, given a fixed payment. A larger payment shortens the time substantially, since more of each payment goes to principal once the interest is covered.
Why must my payment exceed the monthly interest?
Each month, interest accrues on the balance. If your payment is less than or equal to that interest, none of it reduces the principal, so the balance never falls and the loan is never repaid. Your payment must exceed the monthly interest for the loan to make progress, which the calculator checks.
How does a higher payment affect total interest?
Paying more each month pays off the loan faster, so interest accrues over fewer months and the total interest drops sharply. Because interest compounds on the remaining balance, even a modest increase in payment can save a large amount of interest over the life of the loan, especially at high rates.
Does this work for credit card debt?
Yes, as long as you make a fixed monthly payment. Enter your card balance, its annual rate, and the fixed amount you pay each month. Note that credit card minimum payments are usually a percentage of the balance that declines over time, which this fixed-payment model does not capture, but a set payment works perfectly.
What if my rate or payment changes?
This calculator assumes a constant interest rate and a fixed monthly payment. If your rate is variable, or you plan to change your payment, the actual payoff will differ. For those cases, recalculate with updated figures or use an amortization schedule that accounts for changes over time.