Sacramento, CA family law attorney Mary Molinaro explains how child support is determined in California. In California, a state-mandated guideline functions as a mathematical formula for calculating child support. This formula is incorporated into various software programs, as manual calculations can be quite complex. The most commonly used software for this purpose includes Dissomaster and Ex-Spouse. The formula considers several factors, such as the income of the parties, the amount of time each parent spends with the children, and certain deductions. Some deductions may increase net income, while others can decrease it, and these variables collectively contribute to the calculation of the final child support amount.