Massachusetts Child Support Laws: Guidelines, Enforcement, and Penalties

Child support in Massachusetts is set by a formula in the state’s Child Support Guidelines, which combine both parents’ income, factor in the number and ages of the children, and divide the resulting obligation in proportion to what each parent earns.¹ The Massachusetts child support laws that govern that calculation, along with how long support lasts and what happens if a parent falls behind, sit in the 2025 Guidelines and in Chapters 208, 215, and 273 of the General Laws. Support generally runs until a child turns 18, can continue to 21 for a dependent child living with a parent, and can reach 23 for a child enrolled in an undergraduate program.²

How Child Support Is Calculated

The calculation begins with each parent’s gross weekly income. The Guidelines read income broadly: wages, salaries, overtime, tips, self-employment earnings, bonuses, commissions, investment returns, rental income, trust distributions, retirement benefits, workers’ compensation, unemployment, and even lottery winnings all count. Means-tested public assistance such as TAFDC, SNAP, and SSI does not.³

From gross income, each parent subtracts allowable deductions: health insurance premiums, dental and vision insurance for the children, and work-related childcare.⁴ What remains is available income. The parents’ combined available income runs through the Guidelines worksheet, which applies a percentage from Table A tied to the income level, the number of children, and their ages. The resulting support amount is then split between the parents in proportion to their respective incomes.

The Guidelines took their current form on December 1, 2025, replacing the 2023 version.¹ Whatever number the worksheet produces is presumptive: judges follow it unless specific circumstances justify something different, and any departure has to be explained on the record.

Income Caps and Minimum Orders

The formula applies to combined available income up to $450,000 per year. Above that ceiling, the support figure calculated at $450,000 becomes the minimum presumptive order, and the court has discretion to add more for the income above the cap, but at a rate lower than the 10% used at $450,000.⁵

At the low end, the Guidelines shield a paying parent’s basic living costs. If gross income is $301 per week or less, the order should not exceed $15 per week. Between $302 and $391 per week, the cap is $33 per week. A court can set an order at $0 when circumstances warrant it.⁵

When a Parent Is Unemployed or Underemployed

A parent cannot lower a support obligation by choosing not to earn. If a court finds that a parent is capable of working but is voluntarily unemployed, or is earning well below capacity, it can attribute income based on what the parent could reasonably earn rather than actual take-home pay.³

In deciding whether and how much to impute, courts weigh the parent’s education and training, job skills, employment history, health, criminal record, the local job market, and the availability of employers willing to hire them. The age, number, and care needs of the children also factor in. Incarceration is not treated as voluntary unemployment for purposes of setting or modifying a support order.

How Parenting Time Affects the Amount

The default worksheet assumes the children live primarily with one parent and spend about one-third of the time with the other. When custody looks different, the calculation changes.⁵

Roughly equal shared parenting produces a different worksheet result that reflects shared financial responsibility. Split-custody arrangements, where each parent is the primary residential parent for at least one child, have their own worksheet path. If one parent has the children substantially less than one-third of the time, the court can deviate upward. In the zone between one-third and one-half, the 2025 Guidelines expressly allow the court to adjust the order in either direction.⁶

Health Insurance, Childcare, and Medical Costs

Premiums a parent actually pays for health, dental, or vision coverage for the children come out of that parent’s gross income before the worksheet runs.⁴ If the premium also covers someone outside the order and the added cost would unreasonably distort support, the court can exclude some or all of it from the deduction.

Childcare a parent pays out of pocket so they can work or attend school also feeds into the worksheet. Payments covered by third parties do not. The Guidelines separate childcare, which affects the calculation, from extracurricular activities, which do not; whether a summer program counts as childcare turns on the children’s ages, the purpose of the program, and the hours it covers.

Uninsured medical expenses no longer default to a 50/50 split after the recipient parent pays the first $250. Under the 2025 Guidelines, courts have discretion to divide these costs based on each parent’s share of combined available income before support is paid or received.

How Long Support Lasts and College Costs

Chapter 208, Section 28 lets a court order support past age 18 for a child who lives with a parent and depends on that parent financially, up to age 21. It can continue to age 23 if the child is still living with a parent and enrolled in an undergraduate program.²

College contributions are not automatic. A judge can order them or decline. When a court does order a contribution, the 2025 Guidelines cap each parent’s share at 50% of the undergraduate, in-state resident costs at UMass Amherst, including tuition, mandatory fees, housing, meal plan, and books. A judge can go above that cap only with written findings that a parent has the ability to pay more.⁴ The 2025 version added affordability as an explicit factor, including whether a parent would need to liquidate assets or take out loans to pay.

When the Guidelines Don’t Fit: Deviations

The Guidelines number is presumptive. A judge can order more, less, or nothing at all, but the court must make specific findings explaining why. The 2025 Guidelines list fifteen circumstances that can justify a deviation, including:

A child with ongoing extraordinary physical, mental, or developmental needs that carry financial consequences.
A parent with extraordinary health insurance costs.
Extraordinary travel expenses for parenting time.
A rebuttable presumption of substantial hardship whenever the formula would require a parent to pay 40% or more of available income in current child support.
A guidelines result that would leave one household with an unreasonably low share of combined income.
Incarceration of a parent who lacks resources to pay.
Families in which a child has three or more legal parents.

Parents can also agree to deviate if the court finds the agreement fair and reasonable.⁶

Changing an Existing Order

To change an order, a parent files a Complaint for Modification in the Probate and Family Court. The filing fee is $50, and there is no fee if the Department of Revenue is handling enforcement.⁷

Under Chapter 208, Section 28, a court can modify support on either of two grounds. The first is a material and substantial change in circumstances since the original order, such as job loss, a major salary change, new medical expenses, or a shift in custody. The second is an inconsistency between the existing order and what the current Guidelines would produce. That second ground catches many parents by surprise: if the Guidelines were updated after your order was entered, the new formula alone can support a modification, even without a change in either parent’s income. The statute also allows modification to address a child’s health insurance.²

Enforcement When a Parent Doesn’t Pay

The Department of Revenue’s Child Support Services Division (DOR/CSS) enforces orders that are enrolled in its system. Either parent or a caregiver can sign up for DOR/CSS services to establish, enforce, or modify a support order.⁸

The routine enforcement tool is income withholding: support is deducted straight from the paying parent’s paycheck. When that isn’t enough, DOR/CSS has more:

Increased wage withholding, with garnishment raised by up to 25%.
Interception of federal and state tax refunds toward overdue support.
Levies on bank accounts.
Seizure of property to satisfy arrears.
Suspension of driver’s licenses and professional licenses.
Reporting of overdue support to credit bureaus.
Passport denial under federal law when a parent owes $2,500 or more.⁹

Interest, Penalties, and Criminal Consequences

Once arrears exceed $500, Massachusetts assesses both interest and a penalty at 0.5% per month each, calculated on the total overdue balance on the last day of each month.¹⁰ Combined, that is 1% per month, or 12% per year. Neither interest nor the penalty compounds: interest is not charged on accumulated interest or penalties, and penalties are not charged on interest or penalties. But the base balance keeps growing with each missed payment, so the monthly charges keep climbing. These rules apply to arrears owed on or after July 1, 2010.

Willful non-payment can also land a parent in court on contempt. Under Chapter 215, Section 34A, if a parent fails to appear for a contempt hearing, the court can issue a capias to bring them in. When arrears reach six months’ worth of support and DOR has been unable to bring the parent in on a capias, the court issues an arrest warrant.¹¹

Non-support is also a crime. Chapter 273, Section 15A allows a sentence of up to two and a half years in a house of correction or up to five years in state prison, a fine of up to $5,000, or both, for a parent who willfully fails to pay despite the ability or earning capacity to do so. Leaving Massachusetts to avoid paying raises the ceiling to ten years in state prison, a fine of up to $10,000, or both.¹² These penalties are on the books and are imposed in cases where a parent has the means to pay and refuses.

1
Mass.gov. Child Support Guidelines
2
General Court of Massachusetts. Massachusetts Code Chapter 208 Section 28
3
Mass.gov. 2025 Child Support Guidelines Section I – Income Definition
4
Mass.gov. 2025 Child Support Guidelines Section II – Factors to Be Considered in Setting the Child Support Order
5
Mass.gov. Child Support Guidelines 2025 (PDF)
6
Mass.gov. 2025 Child Support Guidelines Section IV – Deviation
7
Mass.gov. Probate and Family Court Filing Fees
8
Mass.gov. Child Support Services Division
9
U.S. Department of State. Pay Your Child Support Before Applying for a Passport
10
Mass.gov. 830 CMR 119A.6.1 – Assessment of Interest and Penalties on Past-Due Child Support
11
General Court of Massachusetts. Massachusetts Code Chapter 215 Section 34A – Contempt, Support or Custody Orders
12
General Court of Massachusetts. Massachusetts Code Chapter 273 Section 15A