Percentage of Obligor's Income Model
As of 2013, nine states and the District of Columbia use the percentage of obligor's income model for calculating child support. If you live in one of these states, you can expect to pay a flat percentage of your income toward your children's needs if you're not the custodial parent. For example, if you have one child, Texas child support takes 20 percent of your pay, and if you have four or more children, the amount of support increases to 35 percent.
Income Shares Model
The majority of states – 38 as of 2013 – use the income shares model for calculating support. These states factor in both parents' incomes on the premise that if you and your spouse didn't divorce, your children would benefit from your combined earnings. The calculations under this model first add your incomes together, and then set aside a portion of the total for your children's needs. If your combined incomes total $60,000, and if you earn $40,000 of that, you would be responsible for about two-thirds of the amount set aside for your children. For example, in Arizona, if you and your spouse together earn $5,000 a month, $794 of this goes to child support if you have one child, and $1,633 would be set aside if you have six children or more.