Is a Balance Transfer Worth the Fee?

A balance transfer trades a 3–5% upfront fee for months of 0% interest. It wins whenever the interest you would have paid on the old card exceeds that fee — which depends on three numbers: the size of the balance, your current APR, and how fast you can pay it down. This calculator simulates both paths month by month with the same payment: the red line is your balance at today's APR, the green line is the same balance on the transfer card, and the moment cumulative interest savings cross the transfer fee is your break-even. Two cautions the math cannot fix: transfers only help if the balance is actually paid off before the promo ends (otherwise the remaining balance reverts to a regular APR), and the discipline that makes them work — paying more than the minimum every month — is exactly what card issuers bet you will not do.