# How to Defend Yourself in Child Support Cases in Court

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Child support is usually an impartial decision on the part of the court. It’s mandatory, and calculations are based on mathematical formulas in all states. Although judges can deviate from the resulting number in isolated circumstances, the support amount is what it is -- the result of an equation. There’s not much you can do to defend yourself against it, but it can help if you understand what goes into the formula and certain factors that may be on your side.

## A Formula Determines the Amount of Support

The majority of states use a formula called the income shares model to calculate the amount of child support. It’s a complex equation, so a judge won’t crunch the numbers with a paper and pencil. The judge will use a computer program and enter your personal information, including your income and that of your ex, how many children you have, as well as how many nights a year they spend with each of you, to determine the amount. The remaining few states use the percentage of income model, which is far less complicated. It’s a flat percentage of the noncustodial parent’s income based on the number of children who need his support. It’s usually about 17 percent if you have one child, but it could go up to as much as 34 percent if you have five children or more -- and it varies slightly by state.

## Request a Deviation

If you feel that the amount of child support determined from your state’s formula is unfair, you can petition the court and ask the judge to deviate from it. However, most states allow this only under specific circumstances, so speak with a local lawyer or legal aid organization to find out what the rules are in your jurisdiction. Deviations can make child support go up instead of down. For example, a judge can increase the amount, deviating from the guidelines, if your child has special needs. But he might reduce it if you have additional children from another relationship to support, or if your child has assets or earnings of his own. Judges can also deviate from the guidelines to accommodate a significant amount of parenting time in states that use the percentage of income model.