Debt Payoff Calculator
See how many months it takes to become debt-free, and how much time and interest an extra payment can save.
About the Debt Payoff Calculator
Becoming debt-free is a timeline question as much as a dollar question — the same balance can take years less to clear with a modest bump in monthly payment. This calculator estimates months to debt-free at your current payment, total interest paid, and how many months an optional extra payment would shave off.
How It Works
The calculator simulates monthly payoff at your base monthly payment, charging interest on the remaining balance each month and applying the rest to principal until it reaches zero. If you provide an extra payment amount, it runs the same simulation again with that additional amount included and reports the difference in months saved.
Interest(month) = Balance × (APR/12); Principal(month) = Payment − Interest(month); the extra-payment scenario adds Extra to Payment before repeating the same steps.
Example
Scenario: An $8,000 balance at 18% APR, paying $300/month, with an optional $50 extra.
Result: About 32 months to debt-free at $300/month; adding the extra $50 saves roughly 6 months and reduces total interest paid.
Assumptions & Limitations
- Assumes the debt behaves like a single revolving or installment balance charging interest monthly on the remaining amount.
- No new charges are added to the balance during payoff.
- If you are juggling multiple debts, run each one separately, or prioritize the highest-rate balance first for the biggest interest savings.
- Does not account for balance transfer offers or promotional 0% periods.