Massachusetts Child Support — Calculator, Laws & Guide (2026)

Understanding Massachusetts child support laws helps both custodial and non-custodial parents know their rights and obligations. This comprehensive Massachusetts child support guide covers how payments are calculated, what income counts, when support can be modified, and how orders are enforced. Whether you are going through a divorce, seeking a modification, or dealing with non-payment, this guide explains Massachusetts’s child support system in plain language.

Verified against Massachusetts statutes and federal OCSE guidelines as of April 2026.

Massachusetts Child Support Overview

Massachusetts uses the income shares model for calculating child support. This model is based on the principle that children should receive the same proportion of parental income they would have received if the family were intact. Both parents’ incomes are combined, and the support obligation is divided proportionally.

Massachusetts uses the income shares model under the Child Support Guidelines (2025 Guidelines effective December 1, 2025). Both parents’ gross weekly incomes are combined, and a base support amount is determined from Table A of the Guidelines Worksheet. The obligation is split proportionally between parents based on their respective income shares. Multipliers adjust for number of children: 1.20 for two children, 1.27 for three, 1.32 for four, and 1.35 for five. The guidelines apply to combined parental incomes up to 450000 per year; income above that cap is at the court’s discretion. The basic calculation assumes children spend approximately one-third of their time with the non-custodial parent; a separate worksheet applies for shared (approximately equal) parenting time.

How Massachusetts Calculates Child Support

The Massachusetts child support calculation considers multiple factors:

1. Determine each parent’s gross income — wages, salary, commissions, bonuses, self-employment income, investment income, and other sources.
2. Calculate combined parental income — add both parents’ adjusted gross incomes together.
3. Apply the guideline schedule — Massachusetts’s guidelines provide a base support amount based on combined income and number of children.
4. Prorate between parents — each parent’s share is proportional to their percentage of the combined income.
5. Add healthcare and childcare costs — these are added to the base amount and divided proportionally.
6. Apply adjustments — parenting time credits, other child obligations, and special circumstances may adjust the final amount.

Online calculator: Use our child support estimator below to calculate your estimated obligation.

What Counts as Income in Massachusetts

Gross income from all sources. Includes wages, salaries, tips, commissions, bonuses, overtime (presumptively excluded unless court includes it), self-employment income (gross receipts minus ordinary and necessary business expenses), rental income, royalties, interest, dividends, trust income, annuities, pensions, Social Security benefits (including SSDI), workers’ compensation, unemployment benefits, disability benefits, veterans’ benefits, military allowances, capital gains, digital assets and nontraditional forms of compensation, and any other income from any source. Expense reimbursements, in-kind payments, personal use of business property, and payment of personal expenses by a business may be included if significant and reduce personal living expenses. If children receive Social Security dependency benefits derived from a parent’s benefit, that amount is added to that parent’s gross income.

Imputed income: YES. Massachusetts courts may attribute (impute) income to a parent who is voluntarily unemployed or underemployed. The court evaluates earning capacity based on the parent’s education, work history, qualifications, past employment, and job market conditions. If the court finds a parent is earning less than they could through reasonable effort, it assigns a hypothetical income amount. When a parent has undocumented or unreported income, the court may impute income based on evidence of asset ownership, lifestyle, expenses, and spending patterns, and may adjust upward for absence of taxes on unreported income. Incarceration may not be treated as voluntary unemployment. The burden of proof falls on the parent seeking attribution.

Deviation factors: Massachusetts courts may deviate from guideline amounts when application would be unjust or inappropriate. Factors include: (1) parties agree and court finds agreement fair and reasonable; (2) child has ongoing special needs or aptitudes with financial consequences; (3) child has ongoing extraordinary mental, physical, or developmental needs; (4) parent has ongoing extraordinary mental, physical, or developmental needs; (5) parent has extraordinary healthcare coverage expenses; (6) parent has extraordinary travel or other expenses related to parenting time; (7) parent has extraordinary childcare costs; (8) parent provides substantially less than one-third of parenting time; (9) when guidelines require payor to pay more than 40 percent of payor’s available income, there is a rebuttable presumption of substantial hardship justifying deviation; (10) combined income exceeds 450000. Any deviation requires specific written findings explaining why the guidelines amount would be unjust or inappropriate.

Healthcare & Childcare in Massachusetts Child Support

Health insurance: Health insurance for the child must be addressed in every child support order. The cost of health, dental, and vision insurance premiums attributable to the child is factored into the child support calculation on the Guidelines Worksheet. The premium cost is shared proportionally between parents based on their respective incomes. Unreimbursed medical, dental, and vision expenses (co-pays, deductibles, uninsured costs) are also shared proportionally between parents. If a parent has access to employer-sponsored or other reasonably priced health insurance, the court may order that parent to maintain coverage for the child.

Childcare costs: Qualifying childcare costs necessary for the custodial parent’s employment, job search, or education are included in the child support calculation. Under the 2025 Guidelines, childcare costs are benchmarked at up to 430 per child per week. These costs are added to the base support obligation and shared proportionally between parents based on their respective income shares. The actual cost is entered on the Guidelines Worksheet and factored into the final support amount.

When Does Massachusetts Child Support End?

In Massachusetts, child support generally ends when the child reaches Child support generally ends at age 18 or upon high school graduation (whichever is later). However, support can continue to age 21 if the child is domiciled in the home of a parent and is principally dependent on that parent for maintenance. Support can extend to age 23 if the child is domiciled in the home of a parent and is principally dependent on that parent due to enrollment in an educational program (excluding costs beyond an undergraduate degree). A court order is required to terminate payments before the child reaches age 23 unless the child is emancipated.. However, support may continue or end earlier based on:

• The child graduates from high school (if still a minor)
• The child becomes emancipated (marriage, military service, self-supporting)
• The child has special needs requiring ongoing support
• College support: YES. Massachusetts courts have discretion to order a parent to contribute to post-secondary educational expenses. By statute, no parent shall be ordered to pay more than 50 percent of the undergraduate in-state resident costs of the University of Massachusetts-Amherst, unless the court enters written findings that the parent has the ability to pay a higher amount. This applies to children up to age 23 who are domiciled with a parent and principally dependent on that parent due to college enrollment. The court may also order support to continue while a child aged 18-23 is enrolled in an educational program. Statutory authority: MGL c. 208 § 28.

Modifying Massachusetts Child Support

When to modify: A child support order may be modified when there is an inconsistency between the current order amount and the amount that would result under the current Child Support Guidelines — this creates a rebuttable presumption that modification is required. Additionally, any material and substantial change in circumstances justifies modification, including: significant increase or decrease in either parent’s income (courts often consider a change of approximately 20 percent or more significant), change in employment status, change in the child’s living or custody arrangements, new healthcare needs of the child, change in childcare costs, or emancipation of a child. No minimum waiting period between modification requests is required.

How to modify: Either parent may file a Complaint for Modification in the Probate and Family Court that issued the original order. Alternatively, if the case is managed by the Massachusetts Department of Revenue (DOR) Child Support Enforcement Division, the parent can request a review and adjustment through DOR. The complaint must be served on the other parent. Modifications can be retroactive to the date of service of the complaint, not to an earlier date. The court applies current Guidelines to determine if the existing order should change. For temporary orders, a Motion to Modify Temporary Order is filed.

Either parent can request a modification. Changes are typically not retroactive to before the date of filing the modification request.

Massachusetts Child Support Enforcement

Massachusetts has multiple tools to enforce child support orders when a parent fails to pay:

• Wage garnishment (income withholding orders to employer); tax refund interception (state and federal); bank account levy/seizure; driver’s license suspension; professional and occupational license suspension; recreational license suspension; passport denial or revocation (for arrears exceeding 2500
• referred to U.S. State Department); contempt of court proceedings (fines and/or incarceration for willful non-payment); credit bureau reporting; lottery winnings interception; liens on real and personal property; insurance settlement interception; increased withholding to 25 percent of income for arrears cases; annual delinquency notices with interest and penalty charges

Contact Massachusetts Department of Revenue (DOR), Child Support Enforcement Division (CSE) at https://www.mass.gov/orgs/child-support-services-division for enforcement assistance.

Additional Massachusetts rules: Combined income cap raised to 450000 per year under 2025 Guidelines (up from 400000). Income definition now expressly includes digital assets and nontraditional forms of compensation. Overtime and secondary job income is presumptively excluded from gross income unless the court finds inclusion appropriate. When the payor would pay more than 40 percent of available income, a rebuttable presumption of substantial hardship applies. College contribution is capped at 50 percent of UMass-Amherst in-state undergraduate costs unless written findings support a higher amount. Social Security dependency benefits received by the child are credited to the paying parent’s obligation. The Guidelines are reviewed and updated every four years by a task force appointed by the Chief Justice of the Trial Court.

Official Sources & Resources

• Massachusetts Department of Revenue (DOR), Child Support Enforcement Division (CSE): https://www.mass.gov/orgs/child-support-services-division
• Federal OCSE: acf.hhs.gov/css
• Cornell LII — Child Support: law.cornell.edu
• Massachusetts Guidelines Statute: Massachusetts General Laws Chapter 208, Section 28 (MGL c. 208 § 28) governs child support in divorce cases. MGL c. 209C § 9 and § 20 govern child support for unmarried parents and modifications. The Child Support Guidelines are promulgated by the Chief Justice of the Trial Court as a court rule (not a statute) under authority of MGL c. 211B § 15. The current version is the 2025 Child Support Guidelines, effective December 1, 2025.

Last verified April 2026. Contact us if you notice outdated information.

Estimate Your Child Support

Use our free child support estimator to calculate estimated monthly payments. Enter both parents’ incomes, number of children, and custody arrangement to see a personalized breakdown based on your state’s formula.

Related Guides

• Massachusetts Divorce Process Guide
• Massachusetts Child Custody Guide
• Massachusetts Alimony Guide
• All Child Support Guides