Massachusetts Child Support Calculator

Massachusetts calculates child support using the income shares model under the Child Support Guidelines (M.G.L. Chapter 208, § 28). Both parents' gross incomes are combined, and a base support amount is determined from Table A of the official Guidelines Worksheet. The obligation is then split proportionally based on each parent's share of combined income. The 2025 Guidelines apply to combined incomes up to $450,000 per year.

Massachusetts uses each parent's gross income from all sources, including wages, salaries, commissions, bonuses, self-employment income, investment returns, and certain government benefits. The 2025 Guidelines apply a graduated bracket system starting at $0 per week up to $7,692 per week ($450,000 annually). Income above $450,000 combined is at the court's discretion, with the Guidelines amount serving as the minimum presumptive order.

The Massachusetts Guidelines Worksheet accounts for two parenting time arrangements: primary custody, where children spend approximately two-thirds of time with one parent, and shared 50/50 custody. Under shared custody, both parents file as 'Single' for tax calculations, while primary custody designates the custodial parent as 'Head of Household.' Shared parenting time typically reduces the base support amount because both parents directly bear child-related expenses.

Massachusetts allows child support modification when there is a material change in circumstances, such as job loss, income increase, or a change in the child's needs. Either parent can file a Complaint for Modification in Probate and Family Court. Only a judge can change the support amount — parents cannot unilaterally reduce payments. The court reviews the current Guidelines Worksheet against the existing order to determine whether modification is warranted.

Beyond the base support amount from Table A, Massachusetts child support includes health, dental, and vision insurance premiums for the child, plus unreimbursed medical expenses shared proportionally by income. Qualifying childcare costs — those enabling a parent to work, attend school, or complete job training — are added separately, benchmarked at up to $430 per child per week under the 2025 Guidelines. Extracurricular activity expenses are handled separately and do not factor into the base calculation.

Massachusetts sets a minimum child support order of $12 per week for payors earning under $210 per week in gross income. Payors earning $211–$249 per week pay $12 plus 20% of income above $210. The effective maximum is based on $450,000 in combined annual parental income under the 2025 Guidelines — amounts above that threshold are at the court's discretion. If child support exceeds 40% of the payor's available income, the payor may request a downward deviation.

Massachusetts child support generally continues until a child turns 18, but extends to age 21 if the child is domiciled with a parent and principally dependent on that parent for support (M.G.L. Chapter 208, § 28). Support can continue to age 23 if the child is enrolled in an undergraduate educational program. For children over 18, the Guidelines automatically reduce support by 25%. A court order is required to terminate payments — parents cannot stop paying unilaterally.

The Massachusetts Department of Revenue (DOR) Child Support Enforcement Division enforces orders under M.G.L. Chapter 119A using administrative tools: wage garnishment, federal and state tax refund interception, bank account seizure, and driver's/professional/recreational license suspension. The DOR also reports non-payment to credit bureaus. For disputed arrears or intentional nonpayment, the custodial parent can file a Complaint for Contempt in Probate and Family Court, where penalties include fines, structured repayment plans, or up to 90 days of incarceration as a last resort.