California’s child support formula

Many in San Francisco may look at cases in which divorced parents are obliged to pay child support and wonder exactly how the court comes up with the amount that is owed each month. The U.S. Census Bureau reports that as recently as 2015, $33.7 billion was owed in child support. Every state has its own method for determining how much of an individual’s obligation will contribute to that amount. 

According to Section 4055 of California’s Family Code, the court considers the monthly net income of the parent who earns the most (HN), and then the same figure of both parents combined to get a total net monthly income (TN). The court then reviews the percentage of time that the higher-earning parent has physical custody of the kids (H). If that number is less than 50 percent, it is added to one; if it is greater than 50 percent, it is subtracted from two. Whatever that result is, it is then multiplied by the following fraction: 

• If TN is less than $800: 0.20 + TN/16,000
• If TN is between $801 and $6,666: 0.25
• If TN is between $6,667 and $10,000: 0.10 + 1,000/TN
• If TN is greater than $10,000: 0.12 + 800/TN

The resulting number represents the percentage of each parent’s income that is to be allocated for child support (K). That number (K) is then multiplied by HN – (H x TN). The final number may then be multiplied by an additional factor if a couple has more than one child. If the final number is positive, the higher-earning spouse pays that to the other. If it is negative, the lower-earning spouse pays its absolute value to the other. 

For example, in a case where HN = $2,000, H = 40 percent, and TN = $3000 for a couple with three kids, the higher-earning parent’s child support obligation will be $560 ((1 + 0.40) x 0.25 = 0.35, 0.35 x ($2000 – (0.40 x $3000)) = $260, $260 x 2(added factor for three kids) = $560).