Kevin Costner's one step closer to finding out what he owes his estranged wife for child support ... a judge tentatively ruled the actor will be coughing up more than $129k a month.
According to new legal docs, obtained by TMZ, the judge in their divorce case says Kevin must pay Christine Baumgartner $129,755 per month in child support. The ruling is tentative, subject to another upcoming hearing though the decision rarely changes.
The figure is a little over half of what Kevin's estranged wife was gunning for ... she requested $248k, a figure Kevin's accountant said included more than $100k for cosmetic procedures.
TMZ broke the story ... Kevin initially offered Christine $51,940, in addition to him paying all the children's expenses, but she scoffed at the figure ... saying the offer was "completely inappropriate."
According to the docs, Kevin and Christine will each be on the hook for 50% of their kids' health care expenses, plus their extracurricular activities and private school tuition.
Kevin is also being ordered to advance Christine $200k for attorney's fees and another $100k in forensic costs.
This child support order is temporary ... there will be a full hearing in the next few months where Kevin and Christine will present evidence of the proper amount of child support -- so it could go up, or down.