How Is Child Support Calculated in New York?

The first step is determining each parent's gross income and making certain adjustments. Income includes wages, salary, overtime, bonuses, commissions, self-employment income, rental income, and other sources. From that gross income, specific deductions are allowed—primarily Social Security and Medicare taxes (FICA) and, if applicable, local income taxes paid on income earned outside New York.

The adjusted incomes of both parents are then added together to arrive at the combined parental income. The CSSA formula applies to this combined figure up to the statutory income cap, which is periodically adjusted by New York State—confirm the current cap with your attorney, as it changes over time.

Once combined parental income is established, a fixed percentage is applied based on the number of children:

• 1 child: 17%
• 2 children: 25%
• 3 children: 29%
• 4 children: 31%
• 5 or more children: no less than 35%

The result is the Basic Child Support Obligation (BCSO)—the total amount both parents together are expected to contribute. This is then divided between the parents in proportion to their respective incomes. So if one parent earns 60% of the combined income, they bear 60% of the BCSO.

Typically, the non-custodial parent (the one with less parenting time) pays their proportional share to the custodial parent as the child support payment.

In addition to the basic obligation, New York courts also address add-on expenses—costs shared by both parents proportionally:

• Health insurance – The cost of health insurance coverage for the child is a mandatory add-on, allocated between parents in proportion to income.
• Child care – Child care costs incurred because a parent is working, looking for work, or in school are mandatory add-ons.
• Educational and extraordinary expenses – Private school tuition, tutoring, and other educational costs can be added at the court's discretion.
• Unreimbursed medical expenses – Out-of-pocket medical costs not covered by insurance are typically shared proportionally.

The CSSA formula is a starting point, not an absolute ceiling. Courts in New York can deviate from the formula when strictly following it would be unjust or inappropriate. Factors that may justify a deviation include:

• The financial resources of each parent and the child
• Physical and emotional health needs of the child
• A non-custodial parent's substantial parenting time (if close to equal)
• Educational needs and expenses
• Tax consequences for either parent
• Agreements between the parents that serve the child's best interests

If a court deviates from the formula, it must state the reasons on the record. Simply agreeing to a lower amount without the court's approval and findings is not enforceable in the same way.

Child support orders are not permanent. Under New York law, either parent can seek a modification in three circumstances:

• There has been a substantial change in circumstances since the order was entered (such as a significant increase or decrease in either parent's income, or a change in the child's needs)
• It has been at least three years since the order was last entered or modified
• There has been a change of 15% or more in either parent's income since the order was entered

If any of these conditions apply, the parent seeking modification can petition the court. The modification is not automatic—a new calculation is run based on current income, and the court enters a new order going forward. Child support cannot be retroactively modified before the date the modification petition was filed.

Child support calculations sound straightforward on paper, but disputes about what counts as income, how to value self-employment earnings, and how to handle add-ons can make them genuinely complex. If you are navigating a child support matter in Erie County Family Court, having an attorney who understands the local court's practices and the details of the CSSA formula can make a significant difference in the outcome.

At Weinrieb Law, attorney Katrina Loss focuses her practice on child support and custody matters throughout Western New York. We offer consultations and are happy to help you understand your rights and obligations.