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If you pay both off completely, you may very well see a score decrease. Fico likes to see at least 1 cc @ between 1-9 % for optimum score value. Everyone's 'sweet spot' is different, though. What your increase would be with that is ymmv because everyone's credit file is different, too. I would guesstimate at least 50 points if you have no negatives. Probably more if this is so.