Two cards, one $300 payment: avalanche vs snowball on $4,100 at 18.9% and $1,200 at 12.9%

Same $4,100 card at 18.9% APR as the earlier examples. This time it is not alone: there is a second card, $1,200 at 12.9%. Total debt $5,300, total payment $300 a month, no new charges on either card. The question is which card gets the extra money — the expensive one (avalanche) or the small one (snowball). The answer is worth $95. The $300 payment itself is worth far more than the order. No advice, just the numbers, so you can run your own.

The setup, and the assumptions

• Card A: $4,100 at 18.9% APR — the card from the earlier articles. Card B: $1,200 at 12.9% APR.
• Payment: $300 a month in total, split between the two cards. No new charges.
• Minimum payment on each card: that month's interest plus 1% of the balance, with a $25 floor. Same rule as the minimum-payment article — Card A's first minimum is $105.58, Card B's is $25.00 (its raw figure is $24.90, so the floor applies). Together the minimums are $130.58 in month 1, leaving $169.42 of extra payment to aim at one card.
• Interest accrues monthly at APR / 12. Same model as the earlier articles, so the single-card baseline matches: $4,100 at $200 a month is 25 months, $890 interest, $4,990 total.
• Avalanche: minimums on both cards, all extra money to Card A (the higher rate). Snowball: minimums on both, all extra to Card B (the smaller balance). Split: the extra is divided evenly between the two cards until one is gone.

Avalanche: pay the expensive card first

Every spare dollar goes to Card A until it is gone, while Card B gets only its minimum.

Card A is gone in month 18. Card B, which only got minimums for 18 months, takes 3 more months and is gone in month 21. Total: 21 months, $835 of interest, $6,135 paid. The principal is $5,300, so the interest is the $835 on top.

Snowball: pay the small card first

Every spare dollar goes to Card B until it is gone, while Card A gets only its minimum.

Card B is gone in month 7 — a first card cleared eleven months earlier than under avalanche. But Card A spent those 7 months growing on minimums only, and the bill for that is $930 of interest in total. Total: 21 months, $930 of interest, $6,230 paid. Same 21 months as avalanche, $95 more interest.

Split it evenly: $150 to each

A third option people actually try — don't pick a target, just split the $300. Card B is gone in month 11, Card A in month 21. Total: 21 months, $912 of interest, $6,212 paid. That lands between the two: $77 more than avalanche, $18 less than snowball. The split is not a compromise that wins on both counts — it wins on neither.

The full stack

All three take 21 months. The order changes the interest by $95 at most, and changes nothing about the finish line. What the order does change is when you get your first win: month 7 under snowball, month 11 under the split, month 18 under avalanche. If clearing a card early is what keeps you paying $300 a month, $95 is a cheap price for it. If you will keep paying either way, avalanche keeps the $95.

What if the payment were only $200 a month?

Same two cards, same minimums, $200 a month in total instead of $300:

• Avalanche: 34 months, $1,398 of interest, $6,698 paid. Card A gone month 30, Card B month 34.
• Snowball: 35 months, $1,545 of interest, $6,845 paid. Card B gone month 13, Card A month 35.

Two things to notice. First, the order now costs $147 and a month — a little more than at $300, because the balances sit longer and the rate gap has more time to work. Second, and bigger: dropping the payment from $300 to $200 costs $563 of interest and 13 months under avalanche. The size of the payment matters roughly six times as much as the order you pay in. Pick an order you will stick to, then put the energy into the payment size.

Run your own numbers

Try the same two cards with your own payment, your own APRs, or your own balances: https://alapha888.github.io/irregular-income-debt-baseline/