About the Debt Payoff Calculator
This debt payoff calculator shows when you will be debt-free and what it will cost. Enter your total debt (or a single loan or card), the interest rate, the monthly payment you make now and any extra amount you could add. You get two payoff timelines side by side — your current plan and the plan with extra payments — plus the months and interest the extra saves.
It suits anyone who wants a quick “how long until I’m free?” answer without listing every account, such as someone with a single personal loan, a consolidated balance, or several cards at a similar rate. If you have debts at very different rates, the snowball and avalanche calculators will build a per-debt plan instead.
You can also set a goal (for example 36 months) to see the monthly payment needed to hit it. Interest is charged monthly at the annual rate ÷ 12, with no new borrowing, and the last payment is just what remains.
With the default inputs, the debt-free in (with extra) is 3 yr 7 mo. Change any value above to recalculate instantly.
How to use the debt payoff calculator
- 1Enter your total debt balance and its interest rate (or a weighted average rate).
- 2Enter what you pay each month now.
- 3Add an extra monthly amount you could realistically afford.
- 4Set a goal in months to see the payment that meets it.
- 5Compare the two timelines and interest saved, then pick your plan.
Formula and method
The calculator steps through your debt one month at a time: interest of balance × r is added (r is the APR ÷ 12) and your payment is subtracted, until the balance hits zero. It runs this twice — once with your current payment and once with the extra added — and compares the months and total interest.
The goal payment uses the standard amortization formula to find the fixed monthly payment that clears balance B in exactly N months. The model assumes no new debt, a constant rate and on-time payments; if a payment is not larger than the monthly interest, the debt is flagged as never repaid.
- B
- Debt balance
- r
- Monthly interest rate = APR ÷ 12 ÷ 100
- P
- Monthly payment (current, or current + extra)
- N
- Goal payoff period in months
Worked examples
$25,000 at 18% with $600 + $200 extra
At $600 a month the debt takes 66 months and about $14,527 of interest. Adding $200 cuts that to 43 months and $8,988 — saving 23 months and roughly $5,539. Being debt-free in 36 months would take $903.81 a month.
$12,000 of card debt at 24% with $350 + $150 extra
Paying $350 on $12,000 at 24% takes almost five years (59 months). Adding $150 finishes in 34 months and saves about $3,947 in interest. A 24-month goal needs $634.45 a month.
$40,000 at 11% with $900 + $300 extra
A $40,000 balance at 11% is paid off in 58 months at $900. An extra $300 finishes in 40 months, 18 months sooner, and saves about $3,656. Four years would need $1,033.82 a month.
Frequently asked questions
How do I calculate my debt-free date?+
Add one month of interest (balance × APR ÷ 12) to the balance, subtract your payment, and repeat until the balance is zero. The number of months is your payoff time — this calculator does that loop for you.
How much do extra payments help?+
A lot, because every extra dollar goes straight to principal and stops accruing interest. On $25,000 at 18%, adding $200 to a $600 payment saves 23 months and about $5,500 in interest.
What rate should I use for several debts?+
Use a balance-weighted average: multiply each balance by its APR, add them up and divide by the total balance. For a precise per-debt plan, use the debt avalanche or snowball calculator instead.
Should I pay off debt or invest?+
Paying off high-interest debt (above roughly 7%–8%) is a guaranteed return that most investments cannot match. For low-rate debt, investing — especially to capture an employer 401(k) match — can make more sense.
Why does the calculator say “never”?+
If your payment is equal to or lower than the monthly interest charge, the balance never falls. You need a bigger payment, a lower rate (for example through consolidation or a balance transfer), or both.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.