On the day the promotional period ends, any balance still on the card starts accruing interest at the regular APR (17% to 30% for most cards in this guide). Not retroactive, the 0% you had was real. But six months at 24% APR on a $5,000 residual costs $600. This chapter walks the three options before that number lands.
All cards covered in this guide use true 0% APR. No interest accrues during the promo. When the promo ends, only future interest applies on the remaining balance.
Every mainstream bank balance transfer card (Citi, Wells Fargo, Bank of America, Chase, Capital One, U.S. Bank) uses true 0% APR, not deferred interest. The long-runway tier is true 0% by definition.
Some store cards and medical financing accrue interest during the promo but waive it if you finish on time. Miss by a day, all the accrued interest hits retroactively. A $5,000 balance at 26% deferred for 18 months that you finished a week late: $1,170 retroactive charge.
Watch for: Home Depot, Lowe's, CareCredit, Amazon Store Card promos, Synchrony retail cards.
If the residual balance is small (under $2,000) and your monthly payment ability has improved, raise the monthly to clear before intro-end. No new product, no credit hit. The cleanest exit.
Best for: Residual under $2,000, monthly capacity headroom
Apply 6 to 8 weeks before intro-end to a card from a different issuer family. A second 3% fee applies. The new 0% intro starts. This is the standard chained-BT play.
Best for: Residual $2,000 to $10,000, credit unchanged or improved
Apply for a personal loan at month 19. Use the loan funds to pay off the BT card balance in full. The remaining debt now amortises over 24 to 60 months at a fixed rate.
Best for: Residual over $10,000, or timeline beyond 21 months
Calculate the remaining balance and the monthly required to clear by month 21. If the figure is comfortable, continue. If not, plan a remediation now.
Soft-pull pre-qualify for both a second BT card (different issuer) and a personal loan. Cost: zero. Information: priceless.
If a second BT, apply now so the 5 to 14 day processing window completes before intro-end. If a loan, apply now so funds arrive in time to pay off the BT.
Initiate the second transfer or use loan funds to pay off the BT card. Confirm in writing.
Verify the BT card balance is $0 by intro-end. The post-intro APR cannot touch what is not there.
If second BT: same discipline, no new purchases. If loan: keep the BT card open with a small recurring charge for credit-mix and utilisation.
Detailed loan-as-bridge comparison.
Best second-BT candidates.
Run the residual-balance math.
Application sequencing for the bridge.
What a second BT does to your score.
Where the loan path becomes the default.