Debt Payoff Calculator
Months to debt free, total paid, and interest from balance, APR, and payment.
What it does
Revolving debt amortizes like a loan in reverse: each month interest posts on the balance, your payment covers interest first, and only the rest cuts principal. Small payments near the interest line barely move the balance, which is how minimums stretch for decades.
The tool above simulates that month by month from balance, APR, and payment. It returns the exact month count, lifetime total, and interest, with the last payment sized down automatically.
Order matters across debts. The avalanche method aims extra cash at the highest rate first and costs least in total. The snowball method clears the smallest balance first for motivation and costs a little more. Both beat spreading extra thin.
Stopping new charges decides everything. Fresh spending refills what payments drain, so the payoff plan starts with the card parked.
How to use
- Enter the current balance from the statement.
- Enter the APR as a percent.
- Enter the fixed monthly payment you can hold.
- Read months and interest, then test a higher payment to see the savings.
Formula
- r
- Monthly rate: APR divided by 12.
- B, P
- Balance and fixed monthly payment.
- ln
- Natural log in the closed form. The tool simulates instead.
Simulation and closed form agree. The last month pays the leftover plus its interest, slightly less than a full payment, which exact totals reflect.
Worked example
Example: $5,000 at 22% APR, $200 a month
Card balance 5,000, APR 22%, payment 200.
- Monthly rate: 0.22 / 12 = 0.018333.
- First interest: 5,000 x 0.018333 = $91.67. Principal cut $108.33.
- Simulation runs 34 months to zero.
- Total paid $6,749.88. Interest $1,749.88.
- At $100 minimums the same debt takes 137 months and $8,678.06 interest.
Reference table
| Monthly | Months | Interest |
|---|---|---|
| $100 | 137 | $8,678.06 |
| $150 | 52 | $2,798.05 |
| $200 | 34 | $1,749.88 |
| $300 | 21 | $1,021.60 |
Limits
- Fixed payment and rate assumed. Rate hikes and fees extend it.
- No new spending included. Fresh charges restart the clock.
- Minimums that fall with balance take longer than fixed payments.
- One debt at a time. Multi debt order needs avalanche sorting.
Common mistakes
- Paying minimums while carrying new charges.
- Closing the oldest card after payoff, which dents credit age.
- Raiding retirement to kill low rate debt.
- Ignoring the APR after balance transfer promos end.
- Spreading extra across all debts instead of aiming one.
Try it yourself
Quick checks. Answers sit tucked under each question.
$2,000 at 0% with $100 a month?
No interest: 2,000 / 100 = 20 months, $2,000 total.
Why does doubling payment more than halve interest?
Extra skips future interest on killed principal. Early principal cuts compound in reverse.
Questions
Avalanche or snowball?
Avalanche (highest rate first) costs least. Snowball (smallest first) motivates most. Pick the one you will follow.
How much extra helps?
A lot. On the example, $200 to $300 cuts 14 months and about $700 interest.
Should I transfer the balance?
Often yes for a 0% window with a small fee, if the debt dies before the promo ends.
Does payoff hurt credit?
Utilization falls, which helps scores. Keep old cards open with tiny activity.
What if payment barely covers interest?
The tool warns you. Raise payment, cut rate, or the balance never moves.
Pay debt or save first?
Keep a small emergency buffer, then attack high rate debt. Both matter; order saves money.