Two $5,000 cards, $125 minimum each, $250 extra a month ($500 total), no new charges. Numbers from this site's public payoff engine. The snowball and avalanche both send the extra to the higher-rate card here, so the order below is the same under either method.
When balances tie, the rate decides
The debt snowball pays the smallest balance first — but when two balances are equal, it needs a tie-breaker, and the rule is the higher rate first. That is the same card the avalanche would pick, so on an equal-balance pair the two methods converge. The only wrong move is paying the cheaper card first. The table keeps the two balances and the $500 a month fixed and flips only the order.
| Cards | High rate first | Low rate first | Gap |
|---|---|---|---|
| 24% / 18% | 28 mo · $2,365.21 | 30 mo · $2,781.20 | $415.99 · 2 mo |
| 29% / 15% | 28 mo · $2,311.34 | 31 mo · $3,320.47 | $1,009.13 · 3 mo |
| 24% / 12% | 27 mo · $1,781.37 | 29 mo · $2,481.26 | $699.89 · 2 mo |
Why paying the cheaper card first costs more
Paying the 15% card first feels like progress — it is gone by month 15. But the 29% card is still charging interest every month until month 31, and by then it has run up $2,816.20. Pay the 29% card first and it is gone by month 17, so it only charges $1,108.76. The cheap card pays a little more interest the other way ($1,202.57 instead of $504.27), but that $698.30 saving does not cover the $1,707.44 the expensive card adds. Net: $1,009.13 more, and 3 more months.
| Order | 29% card interest | 15% card interest | Total |
|---|---|---|---|
| 29% first | $1,108.76 (mo 17) | $1,202.57 (mo 28) | $2,311.34 |
| 15% first | $2,816.20 (mo 31) | $504.27 (mo 15) | $3,320.47 |
The order only matters when you have extra
With no extra money, each card just gets its own minimum, so the order you list them in changes nothing — the difference is $0. The order only starts to matter once you have extra dollars to send to one card, because that is the money whose destination you choose. If you are paying only the minimums, the tie-breaker is not doing any work.
What this means for your plan
If two cards sit at the same balance, send the extra to the higher rate — that is what the snowball's tie-breaker does, and it is also what the avalanche would do. The gap is not cosmetic: on the 29% / 15% pair it is $1,009.13 and 3 months. If the balances differ, the snowball goes smallest-first regardless of rate; the tie-breaker only wakes up when the balances are exactly equal.
Reproduce these numbers
Every figure here comes from this site's public engine. Post both cards and the extra to /api/payoff and you get the months, the total interest and the per-card interest back. The pair is {"debts": [{"name": "A", "balance": 5000, "apr": 29, "minPayment": 125}, {"name": "B", "balance": 5000, "apr": 15, "minPayment": 125}], "extra": 250} — it returns 28 months and $2,311.34 with A first. The engine sorts by smallest balance, breaking an equal-balance tie by the higher rate, so A (29%) is the target. To see the cost of the wrong order, force B first: the same $500 a month then runs 31 months and $3,320.47. Two conventions: APR goes in as a percentage (29, not 0.29), and minPayment is held fixed for the whole run — the same convention every page on this site uses.
Frequently asked
Two cards with the same balance — which do you pay first?
The higher rate first. When two balances are equal, the debt snowball's tie-breaker sends every extra dollar to the card with the higher APR. In the $5,000 at 29% and $5,000 at 15% example, paying the 29% card first clears both in 28 months for $2,311.34; paying the 15% card first takes 31 months and $3,320.47 — $1,009.13 and 3 months more.
Does the order matter if I only pay the minimums?
No. With no extra money, each card just gets its own minimum, so the order you list them in changes nothing — the difference is $0. The order only starts to matter once you have extra dollars to send to one card, because that is the money whose destination you choose.
How much does paying the cheaper card first cost?
In the $5,000 at 29% and $5,000 at 15% case, $1,009.13 and 3 extra months at the same $500 a month. The 29% card runs to month 31 instead of month 17 and charges $2,816.20 of interest instead of $1,108.76.
Why does paying the cheaper card first cost more?
Because the expensive card keeps running while you clear the cheap one. Pay the 15% card first and it is gone by month 15 — but the 29% card is still charging interest until month 31, and by then it has run up $2,816.20. Pay the 29% card first and it is gone by month 17, so it only charges $1,108.76.
Is this the snowball or the avalanche method?
When two balances are equal, they agree. The snowball pays the smallest balance first, but breaks a tie by the higher rate; the avalanche pays the highest rate first. With equal balances both send the extra money to the higher-rate card, so the two methods produce the same order — and the same total.
What if the two balances are different?
Then the snowball goes smallest-balance first, regardless of rate — the tie-breaker only kicks in when two balances are exactly equal. If the balances differ, the smaller one is the snowball's target; if you want the higher rate first instead, that is the avalanche.