Child Support Calculations in Massachusetts

Massachusetts uses the Income Shares model to calculate child support, governed by the Massachusetts Child Support Guidelines and M.G.L. c. 208, §28. The current Guidelines were amended July 31, 2023, with new 2025 Guidelines effective December 1, 2025. Whether you're navigating an uncontested or contested divorce, understanding how Massachusetts calculates child support is essential.

The Income Shares Model

Massachusetts's Income Shares model determines the basic support obligation using Table A (the Child Support Guidelines Chart) based on combined available weekly income and the number of children. The support amount is then allocated between parents proportionally based on their share of combined income.

Combined income cap: $400,000 per year ($7,692/week). Above this cap, the worksheet calculates on the first $400,000; additional support on income over the cap is discretionary and should apply a rate below the 10% marginal rate at the top of Table A.

Determining Gross Income

"Gross income" includes income from any source:

• Wages, tips, commissions, bonuses, and overtime (discretionary treatment)
• Self-employment income (gross minus ordinary/necessary expenses)
• Interest, dividends, rental income, and trust distributions
• Pensions, unemployment, workers' compensation
• Social Security retirement/SSDI (dependency benefits handled specially)
• Stock options, incentive pay, and severance

Excluded: Means-tested benefits (TAFDC, SNAP, SSI), new spouse income.

Attribution: If a parent is unemployed or underemployed, courts may attribute earning capacity. However, incarceration cannot be treated as voluntary unemployment.

Parenting-Time Categories

Massachusetts recognizes three parenting-time configurations:

• Standard/Primary Residence (~2/3-1/3): Children reside primarily with one parent. The other parent pays support.
• Shared (~50/50): Parents share parenting time approximately equally. The worksheet calculates each parent's obligation and nets them; support flows from higher-income to lower-income parent.
• Split: In multi-child families, each parent provides primary residence for at least one child. Obligations are calculated and offset.

Very low parenting time: If the non-residential parent's time is substantially less than one-third, the court may deviate upward.

Estimate Your Massachusetts Child Support

Use our calculator to get a preliminary estimate. For official calculations, use the Massachusetts Child Support Worksheet (CJD 304).

Table B Multipliers and Table C Age Adjustments

After looking up the one-child amount from Table A, apply these multipliers:

• 2 children: 1.40
• 3 children: 1.68
• 4 children: 1.85
• 5 children: 1.94

Table C (ages 18-23): If any child is 18 or older, a 25% reduction applies to reflect different household economics. A child 18+ still in high school is treated as under 18.

Low-Income Minimums and 40% Hardship Rule

Massachusetts protects low-income payors through minimum order tiers:

• $210/week or less: $12/week presumptive minimum
• $211-$249/week: $12 + 20% of amount over $210 (yields $12-$20/week)

40% hardship presumption: If the guideline result would exceed 40% of the payor's available income, there is a rebuttable presumption of substantial hardship justifying deviation. This is a gate for deviation, not an absolute cap.

Child Care, Health Insurance, and Add-Ons

Beyond the basic support, Massachusetts adds these expenses:

• Child care: Shared proportionally by income up to $355/week per child, implemented as an adjustment capped at ±15% of the base order
• Health coverage: Children's health, dental, and vision premiums are deducted from paying parent's gross income and included in the ±15% adjustment. Coverage is "reasonable" if ≤5% of gross and "accessible" if within 15 miles
• Uninsured medical: Recipient pays first $250/year combined; amounts above that and extraordinary items are allocated by court order

Common Calculation Mistakes

• Forgetting Table B multipliers: Always multiply the one-child amount by the appropriate factor (1.40 for 2 kids, etc.)
• Ignoring the ±15% cap: Child care and health coverage adjustments are capped at 15% of the base order
• Missing low-income minimums: Payors earning $249/week or less use the Chart's shaded minimum, not proportional share
• Not checking the 40% threshold: Orders exceeding 40% of available income trigger hardship presumption
• Using outdated guidelines: The 2025 Guidelines take effect December 1, 2025

Modification and Duration

Massachusetts provides pathways to modify support:

• Inconsistency: If the existing order differs from current guideline calculations (no fixed percentage threshold)
• Material change: Any material and substantial change in circumstances
• Health coverage changes: Coverage availability or affordability changes
• Retroactivity limited: Modifications take effect from the date the other party was served

Duration: Support may be ordered for children 18-20 if domiciled with and principally dependent on a parent, and for ages 21-22 if enrolled full-time in undergraduate education. Courts have discretion to order post-secondary contributions (capped at 50% of UMass-Amherst in-state costs unless ability to pay more is shown).

Enforcement and Interest

Massachusetts provides robust enforcement through the Department of Revenue (DOR):

• Interest on arrears: 0.5% per month interest + 0.5% penalty (DOR cases with >$500 arrears; simple, not compounding)
• Income withholding: Default method; DOR may increase by up to 25% for arrears
• Tax refund intercepts: Federal and state refunds applied to arrears
• License suspension: Driver's, professional, and vehicle registrations
• Passport denial: When arrears exceed $2,500

Key Takeaways

• Income Shares model: Table A lookup plus Table B multipliers, allocated by income share
• $400,000/year cap: Discretionary support above this; rate should be below 10%
• Three parenting categories: Standard (~2/3-1/3), shared (~50/50), and split
• Low-income minimums: $12-$20/week for payors earning $249/week or less
• 40% hardship rule: Rebuttable presumption for deviation if order exceeds 40% of income
• Support to age 23: Discretionary for children 18-23 in education

For more information about Massachusetts divorce processes, see our Massachusetts divorce timeline and filing checklist.