Debt Payoff Calculator
Enter your balance, annual interest rate, and monthly payment to see how long it takes to clear the debt — and how much extra you pay in interest.
How it works
How payoff time and interest are computed
Each month, interest of annual rate ÷ 12 is added to your balance, then your payment is subtracted. The tool repeats this until the balance reaches zero, counting the months and summing every interest charge. Paying more than the minimum sends the extra straight to principal, which shortens the payoff time and cuts the total interest you pay.
A worked example
On a balance of $1,000 at 20% APR, the first month adds about $16.67 in interest. A $200 payment leaves roughly $183.33 going to principal. Raise the payment and more goes to principal every month, so the balance falls faster.
Snowball vs. avalanche
The avalanche method targets the highest interest rate first and mathematically minimizes the total interest paid. The snowball method clears the smallest balance first; a 2012 study by Gal and McShane found that the share of accounts already cleared predicted payoff success better than the dollars paid, so snowball can aid motivation.
How to read your result, and caveats
- A long payoff time is a signal to raise the payment if you can.
- Stop adding new high-interest debt while you repay.
- Rates and terms vary; fees and variable rates are not modeled here.
Read next
Debt snowball vs. avalanche: which payoff strategy wins →
Frequently Asked Questions
Does paying a little extra really help?
Yes. Extra payments go entirely to principal, so even a small monthly increase noticeably cuts the total interest and the payoff time.
Why does it say the debt is never paid off?
If your monthly payment is smaller than the interest charged that month, the principal never falls. You must pay more than the monthly interest for the balance to shrink.
Should I use the snowball or the avalanche method?
The avalanche method (highest rate first) saves the most interest, so it is the cheaper choice on paper. The snowball method (smallest balance first) clears whole debts sooner and can keep you motivated, which research links to better follow-through. Pick the one you will actually stick with.
What interest rate should I enter?
Use the APR shown on your statement. If you carry several debts, enter the one you are focusing on, or run the tool once per debt to compare payoff times.
Does this calculator include fees or changing rates?
No. It assumes a fixed rate and no fees, so treat the result as a clean estimate. Promotional rates, late fees, and variable APRs can change the real payoff.
Should I still save while repaying debt?
A small emergency buffer is wise so a surprise expense does not push you back onto high-interest credit. Beyond that, paying down expensive debt usually beats low-interest savings.
This calculator is an educational estimate, not individual financial advice. It ignores fees and variable rates.