If the custodial parent makes a significant amount more than the non custodial, yes, it can be the case, particularly if the non custodial parent has some custody (not joint, but some). The different formulas depend on the state, but ususally both the time spent with the parents and the incomes are taken into consideration.

I think it's all a matter of who makes more $, at least in VA it is. My ex and I have a 60/40 split (with me having 60) and he pays me cs, but I make only 30k and he makes 80k. My fiancee has to pay his ex though. They also have a 60/40 split with him having the 60 but he makes more than she does...so the calculator just had him paying her.

Hope that helps a little. I think it's a (pretty basically at least) a matter of who makes what and what the % split is.

Meaning you have primary custody and he/she pays child support to you? Need more details?

did anyone end up owing the non custodial parent money