Sigma Calculator — 543+ Free Calculator Tools
Enter your balance, APR and monthly payment to see months to debt-free, total paid and interest cost.
Getting started takes less than a minute. Enter your current card balance in dollars — the full amount you owe as shown on your most recent statement, not just the minimum due. Next, type in your card’s annual percentage rate (APR), which appears on your monthly statement or in your cardholder agreement; most U.S. credit cards charge between 18% and 30% APR. Finally, enter the fixed monthly payment you plan to make, every single month, until the debt is gone. Press “Calculate Payoff” and the tool instantly shows how many months it will take to become debt-free, the total amount you will pay, and exactly how much of that total is interest.
The calculator assumes you make no new charges while paying down the balance and that your payment stays the same each month. In real life, interest is added to your balance every month before your payment is applied, so the tool simulates this month-by-month cycle — adding one month of interest, subtracting your payment, and repeating until the balance reaches zero. If your payment is too small to cover even the monthly interest charge, the calculator warns you that the balance would grow forever, which is your signal to raise the payment.
Use the results to compare strategies side by side. First run the numbers with your current minimum payment to see the true cost of the slow road. Then test what happens if you add $50, $100, or $200 more per month — you will watch the payoff time shrink and the interest savings pile up. You can also model a balance transfer offer by entering the promotional APR and adding the transfer fee to the starting balance. Because the calculator runs entirely in your browser, you can experiment with unlimited scenarios instantly and privately, with nothing stored or sent anywhere.
A credit card payoff calculator answers one of the most important questions in personal finance: if I pay a fixed amount every month, when will this debt actually disappear, and what will it really cost me? Credit cards are a form of revolving debt, which means the balance rolls over from month to month and interest charges are added to whatever you still owe. Unlike an installment loan with a fixed end date, a credit card has no built-in finish line — the payoff date is determined entirely by how much you choose to pay.
The reason card debt is so expensive is compound interest working against you. Each month, your issuer multiplies your outstanding balance by a monthly periodic rate (your annual percentage rate (APR) divided by 12) and adds that interest to what you owe. When you make only the minimum payment — typically 1% to 2% of the balance or a flat $25 to $35 — most of your money goes toward that month’s interest and only a sliver reduces the principal. This is why a $5,000 balance can linger for well over a decade on minimum payments alone.
Two more concepts shape your payoff timeline. The grace period is the interest-free window (usually 21 to 25 days) between your statement date and due date — but it only applies if you pay new purchases in full; once you carry a balance, new charges start accruing interest immediately. Your credit utilization ratio — the percentage of your credit limit currently in use — also matters: high balances relative to your limit can depress your credit score even while you pay on time, which is another reason an aggressive debt payoff plan pays dividends beyond interest savings.
This calculator is built for anyone carrying a balance: cardholders deciding between minimum payments and accelerated payoff, households comparing a balance transfer offer against their current card, and borrowers choosing which of several cards to attack first. By turning abstract APR figures into concrete timelines and dollar amounts, it replaces guesswork with a clear, month-by-month amortization of your debt — the same math lenders use, presented in plain language.
The calculator uses the standard loan amortization formula solved for the number of payments. If B is your starting balance, r is the monthly interest rate (APR divided by 12), and P is your fixed monthly payment, the number of months n to reach a zero balance is:
n = −ln(1 − r × B ÷ P) ÷ ln(1 + r)
Total paid is the sum of all monthly payments (with the final payment usually smaller), and total interest is simply total paid minus the original balance. Note the formula only works when your payment exceeds the monthly interest charge (r × B); otherwise the term inside the logarithm is zero or negative, meaning the balance never shrinks — the mathematical signature of the minimum-payment trap.
Worked Example 1. Balance $5,000, APR 18%, payment $150/month. Monthly rate r = 0.18 ÷ 12 = 0.015. Plug in: n = −ln(1 − 0.015 × 5000 ÷ 150) ÷ ln(1.015) = −ln(1 − 0.50) ÷ ln(1.015) = −ln(0.50) ÷ 0.014889 ≈ 0.6931 ÷ 0.014889 ≈ 46.6, which rounds up to 47 monthly payments. Total paid is about $6,983.60 and total interest about $1,983.60 — nearly 40% of the original balance goes to interest alone, and payoff takes about 3.9 years.
Worked Example 2. Balance $8,000, APR 24.99%, payment $200/month. Monthly rate r = 0.2499 ÷ 12 ≈ 0.020825. Then r × B ÷ P = 0.020825 × 8000 ÷ 200 = 0.833, so n = −ln(1 − 0.833) ÷ ln(1.020825) = −ln(0.167) ÷ 0.020610 ≈ 1.7901 ÷ 0.020610 ≈ 86.9, rounding up to 87 monthly payments. Total paid is about $17,369 and total interest about $9,369 — the interest exceeds the original $8,000 balance, and payoff drags on for more than 7 years. This is the brutal arithmetic of high-APR debt at low payments.
Consider a cardholder with a $6,200 balance at 22.99% APR who pays only the 2% minimum payment — about $124 a month. The monthly interest alone is 0.2299 ÷ 12 × $6,200 ≈ $118.82, so just $5.18 of that first payment touches the principal. Running the formula: n = −ln(1 − 0.019158 × 6200 ÷ 124) ÷ ln(1.019158) ≈ 166.9, or 167 months — nearly 14 years.
Over those 167 months the cardholder pays roughly $20,697 in total, including about $14,497 in interest — more than twice the original balance, handed to the lender for the privilege of borrowing $6,200. And this assumes no new charges, no late fees, and no rate increases for 14 years, which is optimistic. The minimum payment is designed to keep the account profitable for the issuer, not to get you out of debt. Seeing these numbers is often the moment borrowers decide to pay more than the minimum.
Take the same $6,200 balance at 22.99% APR, but this time the cardholder commits to a fixed $250 per month — just $126 more than the old minimum. Now the first month’s $118.82 interest charge leaves $131.18 to attack the principal, and every month the interest portion shrinks while the principal portion grows. The formula gives n = −ln(1 − 0.019158 × 6200 ÷ 250) ÷ ln(1.019158) ≈ 34 months.
In under 3 years the debt is gone: total paid is about $8,494, with only about $2,294 in interest. Compared with the minimum-payment path, an extra $126 a month saves roughly $12,200 in interest and wipes out 11 years of payments. This is the single most powerful lever in credit card payoff — payment size matters far more than most borrowers realize, because every extra dollar goes straight to principal and shortens the compounding window.
Paying $150/month: about 47 months (nearly 4 years), costing $1,983.60 in interest on top of the $5,000. Try the credit card calculator above.
Minimums barely cover interest — on $5,000 at 18%, a $100 minimum stretches payoff past 7 years and roughly doubles the interest.
A lot: raising the example payment from $150 to $200 cuts payoff to about 32 months and saves roughly $700 in interest.
Then the balance grows forever — the calculator flags this. You must pay more than the monthly interest charge ($75 on $5,000 at 18%) to make progress.
Often yes if the transfer fee (typically 3–5%) is less than the interest you’d pay — run both scenarios in the calculator to compare.
Usually yes — this is called the avalanche method, and it minimizes the total interest you pay because your highest-rate balance is also your most expensive debt. Direct every extra dollar to the highest-APR card while paying minimums on the rest, then roll that payment into the next-highest card once the first is gone. The alternative, the snowball method (smallest balance first), costs a bit more in interest but gives quicker psychological wins. Either way, use the calculator on each card to see the payoff timeline, then pick the order you will actually stick with.
No — the calculator models a clean payoff scenario: a fixed starting balance, a fixed APR, and a fixed monthly payment with no new charges, fees, or rate changes. This keeps the math transparent and comparisons fair. In real life, new purchases add to the balance, late fees increase what you owe, and penalty APRs can raise your rate — all of which extend the timeline shown. Think of the result as your best-case payoff plan, and protect it by not adding new charges while you pay down the debt.
A 0% introductory APR pauses interest, so every dollar of your payment attacks the principal during the promo period — usually 12 to 21 months. To model it, add the transfer fee (typically 3–5%) to your starting balance and enter 0% as the APR, then check whether the payoff fits inside the promo window. If it doesn’t, re-run with the card’s regular go-to APR for the remaining balance. A transfer usually wins when the fee is smaller than the interest you’d otherwise pay — run both scenarios in the calculator to compare.
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This page provides a credit card payoff calculator. Inputs: card balance (USD), annual percentage rate / APR (%), fixed monthly payment (USD). Outputs: months to payoff, total amount paid, total interest paid. Method: month-by-month amortization simulation; closed-form solution n = −ln(1 − r×B÷P) ÷ ln(1+r), where r = APR ÷ 12, B = starting balance, P = monthly payment. Assumptions: no new charges, fixed payment, fixed APR, monthly compounding. Reference example: $5,000 balance at 18% APR with $150/month payments → 47 months, $6,983.60 total, $1,983.60 interest. Educational tool only; not financial advice.
Sources & methodology: payoff calculations use the standard amortization formula; illustrative figures verified against the on-page calculator. For personalized guidance, consult a qualified financial professional.