How is Child Support Calculated in California?


A question that we are frequently asked is, “How is Child Support Calculated in California?”

Those who have spent any time in a family law court have seen the judge busily tapping away on his computer before rendering an order for child support. Federal law requires that each state develop uniform guidelines to determine the amount of child support in divorce and paternity (parentage) cases. In California, our legislature has enacted a strict algebraic formula for setting this guideline which can be found at Family Code §4055(a). This approach is often criticized for its inflexibility and difficult mathematical calculations. This later problem has been largely resolved by the use of computer programs which aid in making these calculations. As part of our initial consultation with clients, we often run these calculations using various scenarios for income and time share percentage. Please call and schedule an appointment with one of our attorneys so that we can run these calculations for you using the Dissomaster computer program.


For those more mathematically adventurous, here’s the formula:

CS = K [HN – (H%) (TN)]

where …

CS = child support amount;

K = amount of income to be allocated for child support as set forth in Family Code §4055(b)(3);

HN = high earner’s net monthly disposable income;

H% = approximate percentage of time high earner has or will have primary physical responsibility for the children compared to the other parent (where the parents have different time-sharing arrangements for different children, H% equals the average of the approximate percentages of time the high earner spends with each child);

TN = total net monthly disposable income of both parties. [See Family Code §4055(b)(1)]


How is Child Support Calculated in California? Here’s the equation: CS = K [HN – (H%) (TN)]