<prompt> Human: My wife and I have a pretty tight budget that we are generally good at working with and not going over. However, there have been some pretty big events surgeries, home repairs, etc. that have ballooned our credit card balance. I just signed up for a Discover IT card that has a 0 for 18 months with any balance transfers. I am trying to figure out the optimal repayment method - do I pay down the 0 credit card first so as to avoid that interest kicking in in 18 months, or do I pay down my original credit card or a combination...Here are the details:Credit Card Balance, with 6.9 APR - 15,500Average monthly payment we make - ranges from 900 - 1100Average monthly additional credit card purchases: 300 just an average - most months it is less, but then some months it is much more - this isnt ideal, but it is what it is. Once we get our balance under control, this will be manageable within our budgetDiscover IT credit limit - 11,50018 months 0 APR, 10.9 APR after thatShould I go ahead and take the full 11,500 and put that on Discover and then pay the 640month to pay that off in full by the 18mos? That would leave anywhere from 250 - 450 per month on the original credit card, which will most months pay it down some, but will some months not make a dent.OR should I put the majority of my 1000 monthly payment on the account currently accruing interest to pay that down, and then pay just a few hundred a month on Discover? Will the 10.9 interest in 18 months be too big of a hit?Are there any calculators out there I can use to calculate this, taking into account the different APRs and schedules?Thanks for any advice. We are working to keep our credit card spending under control. :  <response>: 18 months is a long time, and in the meantime youre paying 6.9 on a large balance. As long as you wont get back-charged interest if you dont pay off the full balance in 18 months shouldnt be the case with discover, i think youre better off tackling the card that is accruing interest. After 18 months, your credit should be good enough that you can do one more balance transfer, and avoid most of the interest other than 3-4 balance transfer fee. Also, stop using the card with a balance to make purchases. That way youre paying interest on your balance, and all your new purchases. If you dont have another card, use cash or debit instead. 