One balance, one payment plan, one debt-free date.
A $5,000 balance at 20% APR with $200 monthly payments takes about 33 months and costs roughly $1,600 in interest. Pay only the minimum and the same balance can drag on for a decade. The payment amount matters more than almost anything else.
Two levers change everything: pay more per month, or lower the rate (a 0% balance-transfer offer, a call to your issuer). Run your real numbers above — then pick the biggest monthly payment you can sustain without missing it.
Using the standard amortization formula: the monthly rate is your APR divided by 12, and the number of payments comes from how long that rate takes to eat through your balance at your payment size.
Then the balance never shrinks — the calculator will tell you so. You need to pay more than one month of interest (balance × APR ÷ 12) to make any progress at all.
They can, if you pay the balance off before the promo ends and you account for the transfer fee (usually 3–5%). They do not help if you keep spending on the old card.
Usually no. Keeping it open (with a zero balance) helps your credit utilization ratio, which helps your score. Just stop carrying a balance on it.