Massachusetts Child Support Calculator

How Massachusetts Calculates Child Support

Massachusetts determines child support using the Income Shares Model, the standard set out in Massachusetts Child Support Guidelines. Under this model, the incomes of both parents are combined to estimate what they would have spent on the children if the family were intact, and that total obligation is then divided between them in proportion to each parent's share of the combined income.

The calculator above applies that formula to the income and expense figures you enter and shows each step of the math, so you can see exactly how the estimate is built. Because every order ultimately runs through a judge, the guideline figure is a starting point rather than a guaranteed result — the sections below explain what goes into it and where real orders can differ.

Key Rules Behind the Massachusetts Formula

• Massachusetts's guidelines run on GROSS income: income taxes and FICA are never subtracted before the schedule is applied (they are already built into the schedule amounts). Enter income before taxes.
• Massachusetts uses the Income Shares model under the Massachusetts Child Support Guidelines, combining both parents' incomes to determine the basic support obligation.
• The basic obligation is determined from the guidelines worksheet based on combined available income and the number of children.
• A parenting time adjustment applies when the obligor has approximately one-third or more parenting time (approximately 122+ overnights per year — 1/3 × 365 = 121.7). The Massachusetts guidelines use qualitative language ("approximately one-third of the time") rather than a fixed overnight count.
• Health insurance premiums for the children and work-related childcare costs are added to the basic obligation and divided proportionally between parents.
• The guidelines apply to combined annual incomes up to $400,000. For combined income above that amount, the court has discretion to set an appropriate support amount.
• Massachusetts may order support for children over 18 who are still dependent and enrolled in an educational program, up to age 23.
• Courts may deviate from the guidelines when application would be unjust or inappropriate, with written findings required.

What Counts as Income

Child support guidelines are built on each parent's income, so the figure you enter matters more than any other input. Most states start from a broad definition of gross income that includes wages, salary, tips, commissions, bonuses, self-employment earnings, and many forms of government benefits, then subtract specific deductions to reach the income the formula actually uses.

Massachusetts's rules under Massachusetts Child Support Guidelines spell out which deductions apply and whether the formula runs on gross or net income. The calculator's field labels tell you which figure to enter; when in doubt, use your most recent pay stubs and tax return, and confirm the details in the Massachusetts child support laws guide.

How to Establish a Child Support Order in Massachusetts

A child support obligation becomes enforceable only once a court or the state child support agency issues an order. Either parent can request one, and in Massachusetts, as in every state, the local child support agency that operates under the federal Title IV-D program can open a case, locate the other parent, establish paternity if needed, and ask the court to set support using the guideline formula.

When you apply, expect to provide proof of income for both parents, the child's information, and details about health insurance and childcare costs — the same inputs this calculator uses. Running your numbers here first gives you a realistic idea of the order amount before you file.