Credit card payoff calculator

Credit card interest compounds against a revolving balance, so the payment amount and the payoff timeline are two sides of the same equation - fix one and the other falls out of the math. Enter a balance and APR, then choose whether to see how long a fixed payment takes, or how large a payment needs to be to hit a target payoff month.

How the math works

The calculator runs the standard revolving-balance formula: each month, interest accrues on whatever balance remains, the payment covers that interest first, and whatever is left over reduces the principal. Solving for a payoff timeline from a fixed payment just runs that loop forward until the balance hits zero. Solving for a required payment from a target number of months runs the same formula backward, algebraically. Either way, the tool flags the one case that matters most: if a proposed payment is at or below that month’s interest charge, the balance cannot shrink, and the result shows a warning instead of a false payoff date.

Related reading

The math above only works because a payment above the interest line makes progress - the minimum payment trap and why paying only the minimum is a trap walk through why the minimum column on a statement is often close to that line. If you’re deciding how much extra to add, does a small amount extra toward principal really make a difference breaks down the effect in dollars, and what happens if you only ever pay the minimum covers the long-run cost in plain terms.

The formula this calculator uses

monthly interest = balance * APR / 100 / 12
principal paid   = payment - monthly interest
balance          = balance - principal paid
repeat until the balance reaches zero
if payment <= monthly interest the balance never falls

What it assumes without asking

• No further spending on the card
• A fixed payment every month and a fixed APR
• Interest applied once a month to the whole balance

One example, computed in full: $5,000 at 22.99%

What this calculator does not model

• A real statement uses your average daily balance and many cards compound daily, so an actual card costs slightly more than this, never less
• Promotional rates, balance transfer fees and deferred interest offers
• A minimum payment that falls as the balance falls, which is what makes real minimum-payment schedules longer than a fixed payment of the same size

The guide behind this tool

A number on its own does not tell you what to do with it. The first row is the one to look at: at this balance and rate, a payment barely below the monthly interest never clears anything. Credit utilization covers what the balance does to your score while you pay it down.

This tool is a general educational estimate, not financial advice or a payoff guarantee. Real card terms, fees, and promotional rates vary by issuer. See our disclaimer.