How card interest actually accrues
Your APR divided by 12 is charged on the balance every month (issuers technically compound daily, which is slightly worse). At 24% APR, a $6,000 balance accrues about $120 in interest the first month — so of a $200 payment, only $80 reduces what you owe. That's why balances feel immovable: most of the payment is rent on the debt.
The minimum payment trap, quantified
Minimums are typically set around 1-2% of the balance plus interest, engineered to keep you paying for decades. $6,000 at 24% with $200/mo takes about 45 months and ~$2,900 in interest; at $300/mo it's 25 months and ~$1,600. The first extra $100 saves more than a year and roughly $1,300 — the highest-return "investment" most households have available, guaranteed and tax-free at the card's APR.
Faster exits than brute force
A 0% balance-transfer card (usually a 3-5% fee, 12-21 months of no interest) makes every dollar hit principal — worth it if you can clear most of the balance before the promo ends and you stop new charges. A personal loan at 10-14% roughly halves the interest rate for many borrowers and adds a fixed end date. And it's often overlooked: call the issuer and ask for a lower APR — requests succeed more often than people expect.
How to use this calculator
Enter your current balance, the card's APR (on the statement, often labeled purchase APR), and the amount you actually pay each month. The result shows your payoff date and total interest at that pace. Then add an extra amount — try $50, then $100 — and watch both the months and the interest drop. The point is to make the invisible cost visible: paying the minimum on a high-APR balance can mean years of payments and more interest than the original purchases cost. Once you see the number, the fastest wins are usually raising the monthly payment, moving the balance to a 0% transfer offer, or calling to negotiate the rate down.