How long will it take to pay off my debt?
Last updated November 9, 2026
Three things decide how long a debt lasts: the balance, the interest rate and your monthly payment. You can estimate the answer with a simple formula, or let the planner do it for you.
The formula
Let B be your balance, r your monthly rate (APR divided by 12, written as a decimal), and P your monthly payment. The number of months n is:
n = −ln(1 − r × B / P) ÷ ln(1 + r)
It only works if your payment is bigger than the first month's interest (r × B). If it is not, the balance never shrinks.
A worked example
Say you owe $8,000 at 19% APR and pay $300 a month.
- r = 0.19 ÷ 12 = 0.015833
- r × B = 126.67 (the first month's interest)
- 1 − 126.67 ÷ 300 = 0.5778
- n = −ln(0.5778) ÷ ln(1.015833) ≈ 34.9, so about 35 months
What different payments do
Here is the same $8,000 at 19% APR with different fixed payments and no new charges:
| Monthly payment | Time to pay off | Total interest |
|---|---|---|
| $200 | 64 months (5 yrs 4 mos) | $4,774 |
| $300 | 35 months | $2,476 |
| $400 | 25 months | $1,696 |
| $600 | 16 months | $1,057 |
Why more than one debt is harder to estimate
With several debts, each payoff frees up a payment you can move to the next debt. That changes the timeline, and the order you choose matters. The formula handles one debt at a time, so for a full plan it is easier to use a calculator that runs the months in sequence.
Ways to shorten the timeline
- Raise the monthly payment, even by a small amount.
- Lower the rate by asking your issuer or comparing a balance transfer.
- Roll freed-up payments into the next debt.
- Apply windfalls as one-time extra payments.
Use the planner
Enter all your debts and an extra monthly amount. The planner shows your payoff order, your debt-free month and your total interest for each method.
Run your own numbers
Enter your balances, rates and payments to see which debt to pay first and when you could be debt-free.
Related guides
- The real cost of paying only the minimum
- How to pay off $10,000 in credit card debt
- How to pay off debt faster
This article is for education only and is not financial, tax or legal advice. Examples use simplified monthly interest and assume on-time payments with no new borrowing. Your lender's or card issuer's terms control your actual costs.