Debt Payoff Calculator
Calculate how many months it takes to pay off a debt given its balance, APR, minimum payment, any extra monthly payment, and whether you keep the payment fixed or raise it each year. Use it to compare payoff timelines and see how much faster extra or rising payments clear the debt.
Last updated: September 2026
Formula below · 3 sources (CFPB, federalreserve.gov, Wikipedia) · Updated Sep 2026
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About this calculator
With a fixed payment, the calculator solves the amortization equation for time (number of months) rather than payment: N = −ln(1 − B × i / P) / ln(1 + i), where B is the current balance, i is the monthly interest rate (APR ÷ 12 ÷ 100), and P is the total monthly payment (minimum + extra). Each month interest of B × i is added and P is subtracted, so the debt only shrinks if P is larger than the first month's interest; if it is not, the calculator says the payment is too low instead of returning a number. The result can include a fraction of a month, which is the size of the smaller final payment. The Payment Strategy setting lets you model a payment that rises over time: with "Increase 2% yearly" or "Increase 5% yearly", the combined payment is raised by that percentage at the start of each new year, and the calculator steps through the balance month by month to find when it reaches zero. Edge cases: at 0% APR the payoff time is simply B ÷ P; a payment larger than the balance pays the debt off in less than one month. The formula assumes a constant APR and no new charges. Real credit-card minimum payments are usually a percentage of the balance (often interest plus 1%), so they shrink as the balance falls; if you pay only that shrinking minimum, payoff takes far longer than any fixed payment. A useful benchmark: a $5,000 card balance at 22% APR paid with a minimum of interest plus 1% of the balance takes about 19 years and costs about $8,100 in interest, while paying a fixed $150 a month clears it in about 52 months. This calculator handles one debt at a time; to plan several debts with the snowball or avalanche method, run each debt separately or use a multi-debt planner.
How to use
Example 1 — Credit card with an extra payment. You have a $5,000 balance on a card with 22% APR. The minimum payment is $100 and you add $50 extra per month, keeping the payment fixed. Enter 5000 for Balance, 22 for APR, 100 for Minimum Payment, 50 for Extra Payment, and choose Fixed Payment. Result: about 52.0 months (about 4 years 4 months). Verify: i = 22/12/100 = 0.018333; total payment = 150; −ln(1 − 5000 × 0.018333 / 150) / ln(1.018333) = −ln(0.38889) / 0.018167 ≈ 0.9445 / 0.018167 ≈ 52.0 months. ✓ With only the $100 minimum (Extra Payment 0) the same card takes about 136.8 months, so the extra $50 cuts payoff by more than 7 years. Example 2 — Personal loan, no extra. You have $12,000 left on a personal loan at 9% APR with a $250 monthly payment and no extra. Enter 12000, 9, 250, 0, and Fixed Payment. Result: about 59.7 months (just under 5 years). Verify: i = 0.0075; −ln(1 − 12000 × 0.0075 / 250) / ln(1.0075) = −ln(0.64) / 0.007472 ≈ 0.4463 / 0.007472 ≈ 59.7 months. ✓ Total paid is about 59.7 × $250 ≈ $14,930, of which roughly $2,930 is interest. Example 3 — Rising payment. Same card as Example 1, but you raise the $150 payment by 5% at the start of each year. Choose Increase 5% yearly. Result: about 47.1 months, roughly 5 months sooner than the fixed $150 payment.
Frequently asked questions
What is the difference between debt snowball and debt avalanche?
Snowball pays off the smallest balance first regardless of interest rate; avalanche pays off the highest-rate debt first regardless of balance. Avalanche always saves more total interest dollars because you're attacking the most expensive debt first. Snowball produces a "win" sooner because small balances disappear quickly, which is psychologically powerful and helps people stay committed when motivation is the real bottleneck. Research from behavioral economists (notably from the Kellogg School of Management) has shown that people using snowball actually pay off more total debt over time even though the math favors avalanche, because they're more likely to stick with the plan. The right strategy is the one you'll actually follow — if you can stay disciplined with avalanche, do it; if you need early wins to maintain motivation, snowball is fine.
Why is paying only the minimum on credit cards so costly?
Because minimum payments are designed to extend the loan, not retire it. Most credit-card minimums are calculated as a small percentage of the balance (often 1–3%) plus accrued interest. As your balance falls, the minimum payment falls too, so each payment removes less and less principal. A $5,000 balance at 22% APR with a typical minimum of interest plus 1% of the balance takes about 19 years to pay off and costs about $8,100 in total interest — over 1.6× the original balance. Adding even a small fixed extra amount ($50–$100 per month) cuts the payoff time by years and saves thousands. The single most important credit-card rule: always pay more than the minimum, ideally pay in full each month, and if you can't do that, treat each card balance as a high-rate loan to amortize aggressively rather than a flexible credit line.
Should I save for an emergency fund or pay off debt first?
Both, but in a specific order. Most planners recommend: first, build a small starter emergency fund ($1,000–$2,500 or one month of expenses); second, aggressively pay off all high-interest debt (anything above ~7–8% APR, which includes most credit cards, payday loans, and unsecured personal loans); third, build the full emergency fund (3–6 months of expenses); fourth, begin retirement contributions. The reason for the small starter fund first: without any cash buffer, a single unexpected car repair forces you back into the credit cards you're trying to escape. The reason for paying high-rate debt before fully funding emergency reserves: paying off a 22% credit card is a guaranteed 22% return on your money, far better than any savings account. Lower-rate debt (mortgage at 5–7%, student loans at 4–6%) can be paid down concurrently with retirement saving rather than serially.
What are the most common mistakes people make paying off debt?
The biggest is paying only the minimum and assuming the debt is "being paid off" — for revolving credit, the minimum mostly covers interest and the balance shrinks at a snail's pace. The second is taking on new debt while paying off old debt (charging more on the credit card you're trying to retire). The third is consolidating high-rate debt into a longer-term loan to lower the monthly payment, which feels like progress but increases total interest paid. The fourth is using emergency savings to make a one-time debt payoff and then having no cushion when an emergency hits, forcing back into new debt. The fifth is ignoring the interest-rate hierarchy — paying off a 4% mortgage extra while carrying a 22% credit card balance is mathematically backwards. Finally, people often forget that paying down debt is a guaranteed risk-free return equal to the debt's interest rate, which is excellent compared to most other safe-money options.
When should I not use this calculator?
Skip it for variable-rate debt where the APR changes during the payoff period — the formula assumes a constant rate. It is the wrong tool for credit cards with promotional 0% APR balance transfers that revert to a high rate after 12–18 months; for those, model the post-promotional period separately. Do not use it for loans with prepayment penalties without accounting for that cost. It is a poor fit for multiple debts being paid simultaneously — the snowball/avalanche strategy choice is about which debt to attack first, not how a single debt amortizes; use a multi-debt payoff planner for the full picture. For credit cards specifically, real minimum payments shrink as the balance shrinks, so the formula slightly understates the time-to-payoff if you always pay only the minimum. And for student loans with income-driven repayment plans, the standard amortization math doesn't apply — use the federal Student Aid loan-simulator tool.