Income for purposes of child support is broadly defined.
"C. For purposes of this section, "gross income" means all income from all sources, and shall include, but not be limited to, income from salaries, wages, commissions, royalties, bonuses, dividends, severance pay, pensions, interest, trust income, annuities, capital gains, social security benefits except as listed below, workers' compensation benefits, unemployment insurance benefits, disability insurance benefits, veterans' benefits, spousal support, rental income, gifts, prizes or awards. "
Both of the answers provided are a good way to figure it out on your own if you do not have a family law attorney. Most states have the guidelines on thier websites under domestic relations or child support. Look there as well as the sites of many family law attorneys in your area because they may provide links to the state sites or guideluines for you to use.