How do you calculate how much child support should be paid?

California uses a mathematical formula for determining child support.  The formula is as follows:  CS=K(HN-(H%)(TN))

CS= child support amount

K= amount of both parents' income to be allocated for child support

HN= high earner's net monthly disposable income

H%= approximate percentage of time that the high earner has or will have primary physical responsibility for the children compared to the other parent.

When you go to court, the judge plugs the figures into this formula and determines the amount of child support to be paid.

If the amount of child support you are receiving is less than the amount ordered by the court, you can ask the court to enforce the order against your ex.  If your ex is paying the amount ordered by the court, but you are claiming that the amount is less than it should be, you file an Order to Show Cause (court form) asking for a modification of child support.  Your Order to Show Cause should be filed with your declaration stating the supporting facts signed under penalty of perjury and an attached proof of service.  When you file an Order to Show Cause, the court will set a date for a hearing on this issue.  The attached proof of service verifies the date of mailing a copy of the documents you filed with the court to your ex.  You can use a court form proof of service or you can write your own.  If you write your own proof of service, it just says that you are over eighteen and the attached documents were sent via first class mail to________ (name and address of your ex) on ________ (date).  You sign and date at the bottom.  The date you sign should be the same as the date of mailing and the same date you file your documents with the court.

If the court rules in your favor regarding the amount of child support, it may make the order retroactive.  The court will determine how far back to make the additional amount of child support retroactive.