How a balance transfer card actually works
You apply for a new credit card that offers a promotional 0% APR on transferred balances, usually for 12, 15, 18, or 21 months. The issuer pays off your old card, and the balance (plus a 3–5% transfer fee added to the new balance) now sits on the new card at 0% interest. You then pay the new card down during the promo window. Any balance remaining when the promo ends reverts to the card's standard APR.
The three numbers that decide whether it's worth it
First, the transfer fee. On $7,500, a 3% fee is $225 — the cost of admission. Second, the promo length: if you pay $300/month, you need at least 26 months to clear a $7,725 balance at 0%, so an 18-month promo won't finish the job. Third, the post-promo APR: if it reverts to 22.99% — about what most cards charge — the remaining balance becomes expensive fast.
The rule: can you pay it off inside the promo?
The single most important question. If yes: balance transfer is almost always a winner even after the fee, because you pay zero interest on the whole balance. If no: you need to compare the post-promo rate to your current rate. If they are similar, the transfer fee makes the transfer a loss. If the post-promo rate is meaningfully lower than your current rate, the transfer may still pencil out.
Break-even math, simplified
Rough rule: the transfer is worth it if your expected interest saved during the promo window exceeds the transfer fee. On $7,500 at 23.99% APR with 18 months at 0%, you save roughly $1,500 in interest over the promo period. A 3% fee is $225. Easy win — if you actually make the payments.
The "don't use the new card" rule
Most balance transfer cards charge regular purchase APR immediately (no 0% on new purchases), and many issuers apply payments to the 0% balance first — meaning new purchases accrue interest daily with no way to pay them off until the transferred balance is gone. Treat a balance transfer card as a one-way tool: move the debt in, pay it down, do not buy anything with it.
Credit score effects
The application costs 5–15 points from a hard inquiry. New account lowers average account age — another 5–10 points. But when the old card goes to $0 with the new card taking on the balance, your total utilization drops (assuming you keep the old card open), which typically adds 20–40 points. Net effect: usually neutral-to-positive after 3–6 months.
When to consolidate instead
If you have multiple cards, if your credit score is low (balance transfer cards need 680+), or if you can't realistically pay the balance off inside 18–21 months — look at a personal loan consolidation instead. Fixed rates, fixed term, and you can't accidentally re-rack the balance.
Related calculators
For education only. Not financial advice.