Question about Child Support

A friend of mine has recently moved out of his residence.
His wife and 11 yr old daughter still live there.
Legally, when does he need to start paying child support? There is no agreement in place.
He wants to immediately start making payments, but his wife and him can not agree on the amount.

He is going to start making deposits to the family bank account for his daughter and remove his name from the account, but what is his legal obligation at this point?

Thank you,

His legal obligation is to contribute payment towards his child’s reasonable needs. A good way to estimate support would be to use the child support calculator on this website.