The Massachusetts child support guidelines set a standardized formula that the Probate and Family Court uses to calculate every child support order in the state. The current version took effect December 1, 2025, replacing the 2023 guidelines. The formula combines both parents’ weekly gross incomes, applies marginal percentages that scale with the number of children, and divides the resulting obligation between the parents in proportion to each parent’s share of that combined income. The idea behind it is simple: children should receive roughly the same share of parental income they would have received if both parents lived under one roof.
What Counts as Income
The guidelines define gross income broadly. Wages, salary, overtime, tips, bonuses, and commissions all count. So do Social Security benefits, workers’ compensation, unemployment, disability payments, interest, dividends, rental income, and distributions from trusts or retirement accounts. Self-employed parents report business revenue minus legitimate operating expenses.
A few sources are excluded. Means-tested public assistance like Supplemental Security Income (SSI) and Transitional Aid to Families with Dependent Children (TAFDC) does not count. The SSI/SSDI line matters: Social Security Disability Insurance is included because it reflects a parent’s work history, while SSI is need-based and stays out.
If you already pay child support under a separate order for other children, that amount is subtracted from your gross income before the new calculation starts. This keeps a parent from being stretched across multiple orders as if none of the others existed.
When the Court Uses Earning Capacity Instead
A parent cannot lower their support obligation just by earning less than they could. Section I of the 2025 guidelines gives judges authority to attribute income based on earning capacity when actual earnings fall short of what a parent could reasonably make. The court weighs education, job skills, work history, health, criminal record, and the local job market before deciding what the number should be.
Incarceration is treated differently. A parent who is behind bars cannot be considered voluntarily unemployed for purposes of setting or modifying support. That rule carried forward from the 2023 guidelines and reflects a federal regulatory requirement.
Hidden income has its own set of tools. When earnings are undocumented or unreported, a judge can impute income based on lifestyle, spending, and assets, and can adjust the figure upward to account for taxes that were never paid. Expense reimbursements, personal use of business property, and a business paying personal bills all can be counted as income when they reduce a parent’s cost of living.
How the Formula Produces a Number
Section II of the guidelines lays out the calculation. Each parent’s weekly gross income goes in first. The combined income places the family on the guidelines table, and marginal percentages, which rise with the number of children, generate the total support obligation. That obligation is then split between the parents in proportion to each one’s share of the combined income.
The guidelines assume the parent with primary physical custody spends their share directly on the child through everyday household costs. The other parent’s share becomes the weekly support order. When combined income exceeds the top of the guidelines table, the court can set support at the table maximum or order more based on the children’s needs and the family’s standard of living.
One structural change in the 2025 version: Massachusetts law now recognizes that a child can have more than two legal parents, and the guidelines were updated throughout to accommodate that. When a third legal parent is in the picture, the way income is combined and obligations are divided can shift.
Adjustments for Insurance, Childcare, and Other Costs
Once the base amount is set, the guidelines apply adjustments so the order reflects what the family actually spends.
- Health, dental, and vision insurance premiums for the children give the paying parent credit against the order. Only the portion of the premium attributable to the children counts, not the parent’s own coverage.
- Work-related childcare, including daycare and after-school care, is shared proportionally based on each parent’s percentage of combined income.
- If either parent supports other children who live in their household, the guidelines account for that when setting the order.
These adjustments can move the final number a lot. A parent covering $400 a week in daycare and $150 a week for the children’s health insurance will see a very different order than one with none of those costs.
How Parenting Time Changes the Calculation
The standard formula assumes one parent has the child less than one-third of the time. Above that, the math changes.
For parents who split time roughly evenly, the court runs the calculation twice, treating each parent in turn as the primary custodian. The parent with the higher obligation pays the difference. The result is that the higher earner still pays, but less than under a sole-custody arrangement, because that parent already covers a share of daily costs during their own parenting time.
The 2025 guidelines added a new deviation factor for parents whose time falls between one-third and one-half. That fills a gap that used to leave those cases stuck between the standard formula and the shared-custody math.
The Worksheet and Financial Statement
Every case requires Form CJ-D 304, the Child Support Guidelines Worksheet. The 2025 version became effective December 1, 2025, and is available through Mass.gov or the Probate and Family Court clerk’s office.
Everything on the worksheet is weekly. Monthly income divides by 4.33; biweekly divides by two. Before you start, pull together recent pay stubs, your last tax return, W-2s, and documentation showing the weekly cost of the children’s health insurance and any childcare. The form takes each parent’s gross income, applies deductions for taxes, existing support orders, and health insurance, runs the guidelines percentages, and produces a presumptive weekly support amount.
You also file a Financial Statement. Parents earning under $75,000 a year use the short form (CJD 301S); those at or above $75,000 use the long form. It’s a sworn document covering income, expenses, assets, and liabilities, and the judge relies on it when checking the worksheet numbers. Both parents’ worksheets and financial statements are filed with the court, and either parent can challenge the accuracy of the other’s figures at the hearing.
Most final orders include an automatic wage assignment, meaning the payor’s employer withholds support from each paycheck. The Department of Revenue’s Child Support Services Division (DOR/CSS) typically processes those payments, collects from employers, and distributes to the receiving parent.
When a Judge Can Deviate from the Formula
The worksheet number is presumed correct, but Section IV of the guidelines lets the court order more or less when strict application would be unjust. If a judge deviates, the reasons go in writing, along with what the guidelines amount would have been.
The 2025 guidelines recognize deviation grounds including:
- An agreement between the parents that the court finds fair and reasonable.
- A child’s special needs, aptitudes, or extraordinary mental, physical, or developmental needs, or the same for a parent when those needs carry financial consequences.
- Extraordinary health insurance costs.
- Travel costs for parenting time, particularly when parents live far apart.
- Extraordinary childcare costs beyond what the standard adjustment captures.
- A payor with substantially less than one-third parenting time.
- Parenting time between one-third and one-half, new in 2025.
- A child with more than two legal parents, also new in 2025.
- An incarcerated payor with insufficient resources, where the order can be set at zero.
- Self-support impairment, when the formula would leave a parent unable to meet basic needs.
- Gross disparity in household living standards.
- Impact on reunification when a child has been temporarily removed under child welfare proceedings.
- A general catch-all for any situation where the formula produces an unjust result or a result not in the child’s best interest.
There is also an automatic hardship trigger. When the formula would require a payor to hand over 40% or more of their available income as current child support, the guidelines presume substantial hardship. That doesn’t guarantee a reduction, but it puts the court on notice that the case needs a closer look.
How Long Support Lasts
Child support does not automatically stop at 18. Under Chapter 208, Section 28, a court can order support up to age 21 if the child lives with a parent and depends primarily on that parent for financial support. Support can extend to age 23 if the child is enrolled in an educational program and remains dependent, though orders cannot cover costs past an undergraduate degree.
The 2025 guidelines address college expenses directly. A court can order a parent to contribute, but no parent can be ordered to pay more than 50% of the in-state undergraduate cost of attendance at the University of Massachusetts Amherst unless the judge makes written findings that the parent can afford more.
Modifying an Order
Support orders can be changed. Under Chapter 208, Section 28 (for divorce cases) and Chapter 209C, Section 20 (for unmarried parents), a parent can seek modification by showing either a material and substantial change in circumstances or an inconsistency between the existing order and what the current guidelines would produce.
Common triggers include a significant income change, the end of childcare costs as children age out, a shift in health insurance coverage, or the emancipation of one child on an order that covers several. To start the process, you file a Complaint for Modification and serve it on the other parent.
The inconsistency ground is worth knowing about. If your existing order simply doesn’t match what today’s guidelines would produce, that gap alone can support a new order without any dramatic life event. One caveat: if the original order came out of an approved deviation, the court will look at whether the facts behind that deviation still hold.
Enforcement If a Parent Falls Behind
DOR/CSS has broad enforcement authority. Wage assignment is the workhorse, and when arrears build up, DOR/CSS can bump the withholding by 25% until the past-due balance is paid off. Other tools include suspending a parent’s driver’s, professional, business, or trade license; levying bank accounts, where a notice freezes the account for 21 days before funds transfer to DOR/CSS; intercepting state and federal tax refunds, unemployment, workers’ compensation, insurance claims, and public pensions; seizing vehicles, boats, vacation properties, and lottery winnings; charging interest and penalties on arrears over $500; and pursuing contempt in court, which can result in fines or jail.
One rule matters more than any single enforcement tool. Under federal law, each child support payment becomes a judgment by operation of law the moment it comes due, and no court can retroactively reduce or forgive it. Arrears keep accumulating whether a parent loses a job, gets sick, or goes to prison, until a court modifies the order going forward. If your circumstances change, filing for modification promptly is the only way to stop the balance from growing beyond what any judge can later erase.
Taxes
Child support has no federal tax consequences on either side. The paying parent cannot deduct it, and the receiving parent does not report it as income. That’s true regardless of the amount, and it’s different from alimony, which has its own separate deductibility rules that changed under the Tax Cuts and Jobs Act. Parents sometimes mix the two up, but child support has never been deductible.