See how Massachusetts calculates child support under the current Guidelines, then get your exact figure from the state's official worksheet. Updated for the Guidelines effective December 1, 2025.
Guidelines information, not legal advice. Child support in Massachusetts is governed by the Child Support Guidelines, but courts may deviate based on hardship, extraordinary circumstances, or the parties' agreement. Shared custody, self-employment income, and other complex factors require attorney review. The official worksheet produces the presumptive guideline figure, not a court order. Schedule a consultation for advice on your specific situation.
Massachusetts child support is set by an official worksheet that the Probate and Family Court uses in every case. Rather than give you an estimate that could differ from the court's, we point you straight to the state's own calculator, so the number you see is the number the court uses.
Open the Official Massachusetts Worksheet (CJ-D 304)Official Massachusetts Trial Court form, effective December 1, 2025. Opens on mass.gov.
The worksheet asks for a handful of figures. Have these ready before you start:
Shared custody, self-employment, variable income, and combined incomes above the $450,000 guideline cap can all change the result. We will review your situation and tell you what to realistically expect.
Massachusetts uses an income shares model. Both parents' incomes are combined to determine what parents in that income bracket typically spend on children — then each parent contributes their proportional share.
Both parents' gross weekly incomes are added together to produce the Combined Available Income (CAI). This reflects that the guidelines ask: what would these parents together spend on children if they were living in the same household?
The Guidelines Schedule sets the Basic Child Support Obligation (BCSO) based on the CAI and the number of children. This represents the total amount both parents are expected to provide for the children's basic needs.
Each parent's share is proportional to their contribution to the CAI. Add health insurance, dental/vision, and 75% of child care costs — then credit each parent for expenses they directly pay.
When both parents have at least 1/3 of overnights (121+ nights/year), the guidelines apply a parenting time adjustment that typically reduces the obligation. The more equal the time, the smaller the payment.
For combined incomes above $450,000 per year, which is the Guidelines maximum as of December 1, 2025, the court has discretion. The guidelines amount is a baseline, and courts may order more or less depending on the children's needs and the parents' lifestyle.
A court may deviate from the guidelines if payment would leave the payor below the federal poverty line, if the payor supports children from another relationship, or if other extraordinary circumstances exist.
Self-employment income is adjusted for legitimate business expenses. Bonus, commission, and other variable income may be averaged over recent years. Courts also have power to impute income to a voluntarily underemployed parent.
Child support and custody are closely linked. Understanding how Massachusetts classifies custody arrangements helps you understand how support is calculated.
One parent is the primary residential parent — the child lives with them most of the time. The other parent typically has parenting time (formerly "visitation") that is less than 1/3 of overnights per year.
Both parents have at least 121 overnights per year (1/3 of 365). This is increasingly common in Massachusetts. The guidelines include a parenting time adjustment that reflects the increased costs for both parents when caring directly for children.
Legal custody governs major decisions about the child's education, healthcare, and religion. It is separate from physical custody. Joint legal custody is the norm in Massachusetts — both parents share decision-making authority.
In families with multiple children, different children may primarily reside with different parents. This "split custody" arrangement involves a separate calculation for each child, with the net obligations offset against each other.