Massachusetts Child Support Calculator
Estimate your presumptive weekly order under the current Guidelines, see the full worksheet math, then verify your figure with 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.
Child Support Estimator · 2025 Guidelines
This estimator follows the official Massachusetts Child Support Guidelines Worksheet (CJD 304, effective December 1, 2025) line by line, including Tables A, B, and C. All amounts are weekly (monthly amount ÷ 4.33 = weekly).
Verified against the official CJD 304 worksheet, July 2026.
Parent A = the parent the children primarily live with. Parent B = the other parent.
Child care costs paid (if any)
Weekly amount each parent pays per child. The Guidelines share these up to a benchmark of $430 per child per week.
Social Security dependency benefits (uncommon)
Only if a child receives a Social Security dependency benefit because of a parent's retirement or disability.
Calculate Your Exact Figure
Massachusetts child support is set by an official worksheet that the Probate and Family Court uses in every case. Once you have your estimate above, verify it with the state's own calculator, so the number you file 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.
What You'll Need
The worksheet asks for a handful of figures. Have these ready before you start:
- Each parent's gross weekly income, before taxes, from all sources
- The number of children covered by the order
- The parenting schedule, including the number of overnights with each parent
- Weekly cost of the children's health and dental insurance, and who pays it
- Weekly child care costs, and who pays them
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.
How Massachusetts Child Support Is Calculated
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.
Combine Both Parents' Incomes
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?
Parent A Income
+ Parent B Income
Look Up the Basic Obligation
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.
Schedule(CAI,
# children)
Allocate by Income Share
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.
(Parent's % × Total)
− Expenses Paid
Factors That May Adjust the Guidelines Amount
Shared Physical Custody
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.
Income Over the Cap
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.
Hardship Deviations
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 & Variable Income
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 Custody in Massachusetts
Child support and custody are closely linked. Understanding how Massachusetts classifies custody arrangements helps you understand how support is calculated.
Primary Physical Custody
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.
Shared Physical Custody
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
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.
Split Custody
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.