Minimum Payment Worked Examples: The Cost of Extra Payment

July 20, 2026

Three worked examples: a minimum-only payoff, the same balance with a fixed extra payment added, and a two-card avalanche-vs-snowball comparison.

Example 1 — Minimum-Only Payoff Baseline

Balance: $6,000. APR: 22%. Formula: greater of $25 or 2% of balance, plus interest.

Month 1 minimum payment:
2% of $6,000 = $120 (beats the $25 floor)
Monthly interest = $6,000 × (22% ÷ 12) = $110
Minimum payment = $120 (the 2% already reflects balance; interest is paid from within it per the calculator's simulation)

Simulated forward month by month at this shrinking-balance formula, this balance takes roughly 11-12 years to reach zero and costs several thousand dollars in total interest — consistent with the credit card minimum payment calculator’s own $8,000-balance example reaching 142 months.

Example 2 — Same Balance With a $100 Fixed Extra Payment

Same $6,000 balance and 22% APR, but paying $100 above the calculated minimum every month instead of letting the payment shrink with the balance.

Because a fixed extra payment doesn’t decline as the balance does, it breaks the shrinking-payment mechanic entirely — the payoff shifts from an open-ended, multi-year crawl to a bounded timeline, typically cutting both the payoff time and total interest substantially compared to Example 1. The exact months and dollar savings depend on the specific formula and APR, which is why running your own balance through the credit card minimum payment calculator with an added fixed amount is worth doing directly rather than relying on a rule of thumb.

Example 3 — Avalanche vs. Snowball on Two Cards

Card X: $3,000 balance, 27% APR
Card Y: $1,500 balance, 15% APR
Extra payment available: $150/month (on top of both minimums)

Avalanche: all $150 extra goes to Card X first (highest APR, 27%), since it accrues interest fastest — Card Y gets only its minimum until Card X is fully paid off, then the freed-up payment rolls onto Card Y.

Snowball: all $150 extra goes to Card Y first (smallest balance, $1,500), reaching zero balance faster in absolute time — Card X gets only its minimum until Card Y is cleared, then the freed-up payment rolls onto Card X.

Avalanche minimizes total interest paid across both cards combined, since it targets the faster-accruing balance first. Snowball clears an entire card sooner, which the CFPB notes can provide a motivating early win — even though it isn’t the lower-total-interest ordering in this case, since Card Y’s rate (15%) is meaningfully lower than Card X’s (27%). See debt avalanche vs. debt snowball for how to decide which trade-off fits your situation.

Running These Yourself

Enter any balance, APR, and minimum payment formula into the credit card minimum payment calculator to see the exact month-by-month simulation for your own numbers — including how much adding a fixed extra payment changes the total timeline and interest cost compared to minimum-only payments. The same figures appear on your statement in a standardised form — how to read your card’s minimum-payment warning box explains what it is telling you.