Massachusetts Child Support Guidelines and Calculator

Massachusetts child support isn't negotiable in the way property division is. The court applies a formulaic calculation using the Child Support Guidelines — and deviating from the result requires specific justification that the judge must approve on the record.

Here's how the calculation works, what income counts, and when the court will deviate from the standard amount.

How the Guidelines Worksheet Works

The Massachusetts Child Support Guidelines (updated periodically by the Trial Court) use both parents' gross incomes to determine a weekly support obligation. The calculation follows Form CJD 304 (Child Support Guidelines Worksheet):

1. Determine each parent's gross weekly income — wages, salary, tips, commissions, bonuses, self-employment income, Social Security, disability, unemployment, workers' comp, pensions, annuities, rental income, dividends, interest, and trust income
2. Apply allowable deductions — federal and state taxes, Social Security/Medicare contributions, existing child support orders for other children, health insurance costs for the children, dental/vision insurance, childcare costs necessary for employment
3. Calculate combined available income — both parents' incomes minus deductions
4. Apply the Guidelines percentage — based on combined income and number of children (ranges from approximately 20% for one child to 30%+ for three or more children at lower income levels)
5. Apportion between parents — the non-custodial parent's share is proportional to their percentage of combined income

Income Cap and High-Income Cases

The Guidelines apply to combined gross incomes up to $400,000. For combined income above this threshold, the court has discretion to order support above the Guidelines amount based on the children's needs and the family's standard of living.

For very high-income families, the court typically considers the children's actual expenses (private school tuition, extracurricular activities, medical needs) rather than applying the standard percentage.

Common Deviations

The court can deviate from the Guidelines result — ordering more or less than the formula produces — when:

• A child has extraordinary medical, educational, or special needs
• The child has independent income or assets
• A parent has extraordinary expenses (high medical costs, other support obligations)
• The custody arrangement involves substantially equal parenting time (true 50/50 schedules may reduce the support amount)
• Application of the Guidelines would be unjust or inappropriate given the parties' circumstances

Any deviation must be documented on Form CJD 305 (Proposed Findings and Determinations for Child Support) with the judge's written findings explaining why the standard amount doesn't apply.

Modifying Child Support After Divorce

Child support is always modifiable. Either parent can file a Complaint for Modification (filing fee: $50) when there's a material change in circumstances:

• Job loss or significant income change
• Child's medical or educational needs change
• Custody arrangement changes
• Either parent relocates
• The existing order has been in place for three or more years (a three-year review allows recalculation even without a dramatic change)

The modification takes effect from the date of filing the complaint, not the date the judge signs the new order — so filing promptly when circumstances change matters.

Child Support Duration

Under Massachusetts law, child support continues until the child:

• Turns 18 (if not enrolled in school)
• Turns 21 (if still dependent and enrolled in an educational program)
• Turns 23 (if still dependent and enrolled in an educational program, by court order)
• Becomes emancipated, marries, or enters military service

The court has discretion to extend support through age 23 for children pursuing higher education, but this is not automatic — it requires a specific court order.

Getting the Calculation Right

An error on the Guidelines worksheet — miscategorizing income, missing a deduction, using net instead of gross — produces a support number that's either too high or too low, and it stays in place until someone files to modify it. The Massachusetts Divorce Filing Process Guide includes a child support calculation walkthrough that matches each line of Form CJD 304 to the documentation you need, helping you present an accurate calculation the first time.

See more Massachusetts guides →