Credit Card Payoff Calculator

What this calculator does

Every card statement contains a quiet piece of behavioral engineering: the minimum payment, printed exactly where your eye lands. This calculator prices that suggestion against a plan of your own. Enter your balance, APR, and a fixed monthly payment; it returns your payoff date and total interest — then runs the same balance through a typical declining minimum (2% of the balance with a $25 floor) so the comparison sits in the same panel, in dollars and years.

How the math works

With a fixed payment, the card behaves like any loan: each month interest = balance × (APR ÷ 12); the payment covers interest, the remainder cuts principal. The payoff time follows the standard formula n = −ln(1 − B·r/M) ÷ ln(1 + r).

With minimums only, the payment itself is recalculated every month as max(2% × balance, $25). Because the payment shrinks with the balance, principal reduction slows continuously — and if the percentage minimum is below the monthly interest rate, the balance never falls at all. The calculator simulates this month by month rather than pretending a formula fits it.

A worked example

A $6,500 balance at 24.9% APR, attacked with a fixed $250 per month:

• Monthly interest at the start: 6,500 × (24.9% ÷ 12) ≈ $135 — more than half of the first payment
• Payoff: about 38 months (3 years 2 months)
• Total interest: roughly $2,940

Now the same balance on minimum payments: 2% of $6,500 is $130 — less than the $135 of monthly interest. The balance doesn’t shrink; it grows. This isn’t an edge case invented for effect: it’s the direct arithmetic of a 2% minimum meeting a 24.9% APR, and it’s why regulators require statements to disclose the long-run cost of minimum payments. Even where the issuer’s formula (interest + 1% of principal) technically amortizes, payoff routinely stretches past 20 years with more paid in interest than the original balance.

Common mistakes

1. Paying a percentage-of-balance minimum and expecting progress. If the minimum percentage is below the monthly interest rate, the balance can grow even while you pay — check that your payment clears the interest line first.
2. Continuing to charge while “paying it off.” New spending on the same card while executing a payoff plan is a treadmill; the balance this calculator projects assumes no new charges.
3. Letting the payment shrink as the balance falls. Minimum payments decline with the balance by design — fixing your payment at today’s minimum, rather than letting it drift down, is what actually shortens the payoff.
4. Ignoring which balance a payment applies to. With multiple APRs on one card (purchases vs. cash advances), issuers must apply amounts above the minimum to the highest-rate balance first — assuming otherwise can misjudge how fast the expensive balance actually falls.

Practical tips

1. Fix your payment at today’s minimum — forever. The simplest effective trick: whatever your minimum is this month, keep paying that amount even as the required minimum falls. It converts the issuer’s formula into a fixed-payment plan without budgeting a single new dollar.
2. Push the payment above the interest line first. Progress only starts when your payment exceeds the monthly interest (balance × APR ÷ 12). Below that line, you’re renting the debt.
3. Stop adding while you subtract. A payoff plan with ongoing new charges is a treadmill. Move daily spending to a debit card or a second card that’s paid in full monthly, so the target balance only moves one direction.
4. Multiple cards? Order matters. Attack the highest APR first while paying minimums elsewhere — or run your full debt list through the debt snowball calculator to compare orderings with real numbers.

After the payoff

The habit that killed the balance — a fixed monthly amount leaving your checking account — is worth keeping. Redirect it: the same $250 that cleared this card becomes an emergency fund in months (size it with the emergency fund calculator) and after that, compounding growth (see the compound interest calculator). The cash flow already exists; only its destination changes.