Hi,
I'm re-building my credit and I can view my credit score online. Last month it was 583, and this month it changed to 579. I have paid all bills in full. Could it be that in the last cycle my balance was just $3 under the credit limit?

Thank you!

Yes, it's called credit to debit ratio.
How much credit you have to how much credit your actually using is taken in to consideration. The higher your credit to debit ratio is the lower your credit score is.

Thanks!
I just got another card, in case I need to spend a lot.
What would be considered a good ratio? My first card has a limit of $1000. If my balance is 50% of the limit, would it be all right? I figure that if I have a very small balance, say, only $50 every month, that would not be good either?

Thank you!

A good credit to debt ratio would be that you are barely using any of your available credit. Key word being available credit, because only active revolving trades are considered good credit to debit ratio. Closed and unactive lines are usually not considered. Your credit line amount and your available credit is taken in to consideration. Your credit line is $1000 and your available credit is $500. Then your credit to debit ratio is 50/50 which is considered average. You want to build your credit line up by making on time payments and by paying over the minimum due. So your credit line goes up and your credit to debit ratio does down.