A 0% intro-APR balance transfer moves existing debt onto a new card that charges no interest for a set window — often 12 to 21 months. Used with a plan, it can dramatically speed up payoff because every dollar goes to principal.

The catch is the transfer fee, usually 3–5% of the amount moved. Compare that one-time fee against the interest you'd otherwise pay; for a high-APR balance, it often still comes out ahead.

The discipline that makes it work: clear as much as possible before the intro period ends, because the regular APR then applies to whatever remains. Avoid new spending on the card while you pay it down.