Massachusetts Child Support Calculator

At $6,000 per month in combined monthly gross income, Massachusetts's guidelines produce roughly $849/month for 1 child, $1,187/month for 2 children, $1,426/month for 3 children, $1,569/month for 4 children. These figures come from running Massachusetts's own guideline formula, but they hold several things constant -- assumes the higher earner has 65% of the combined gross income shown and the children live primarily with the other parent (worksheet Box 2), all children under 18, with no health or dental premiums, other support, or child care entered. Massachusetts calculates weekly; these are the weekly orders converted to monthly (× 52 ÷ 12). Your actual number depends on both parents' incomes, your parenting-time schedule, and add-on costs like childcare and health insurance, so run the calculator for your own case.

Massachusetts uses the Income Shares model. Massachusetts applies a tiered percentage formula (Table A) to the parents' combined weekly gross income after health and dental premiums and other support paid, scales it for the number of children and any children 18 or older, and splits it by income share. There is no overnight count: the worksheet asks whether parenting is shared, primarily with one parent (about 2/3 of the time), or split.

Massachusetts's guideline runs on combined weekly available gross income. That distinction matters: entering gross income into a formula built on net income (or the reverse) produces a materially wrong figure. Most states count income from essentially any regular source -- wages, self-employment, bonuses, commissions, rental and investment income, and many benefits -- not just salary.

Not necessarily. In Massachusetts: no overnight threshold. Three plans — shared, primary residence (about 2/3 of the time), or split. Anything in between is a judicial deviation. Because the guideline also weighs each parent's share of income, a significantly higher earner can still owe support at an even time split.

This calculator's core formula has been verified against the primary source, with any unimplemented rules listed openly rather than hidden. It implements the guideline in effect as of 2025-12-01, and a human last checked it against the primary source on 2026-09-29. Sources: 2025 Massachusetts Child Support Guidelines (effective December 1, 2025); Child Support Guidelines Worksheet, CJD 304 (12/1/25); 2025 Child Support Guidelines Chart. It is still an estimate, not a court order -- a judge can order a different amount, and this is not legal advice.

The Massachusetts guideline this calculator implements took legal effect on 2025-12-01. States revise their guidelines periodically -- federal rules require each state to review its guidelines at least once every four years -- so a figure from an older calculator or article may reflect a superseded rule.

Implements the 2025 guidelines effective December 1, 2025: a $450,000 combined-income cap, $15 minimum order, $301/$391 low-income tranches, $430-per-child child-care limit, and Table B factors of 1.40/1.68/1.85/1.94. Much Massachusetts material online, and many other calculators, still use the 2021 figures ($400,000, $12, $210/$249, $355). The arithmetic follows the official electronic worksheet (CJD 304) line for line — its embedded calculation scripts, including where it rounds to whole dollars and whole percentages — and was checked against an independent transcription of those scripts. The published 2025 Guidelines Chart and the worksheet's Table A formula agree at every one of the chart's 1,104 rows, but the chart skips one row at each of four column breaks on its last page (after $6,995, $7,445, $7,895 and $8,345 of weekly income). For the 49 weekly incomes in those gaps, reading the chart gives $1/week less than the formula. This calculator uses the formula, as the electronic worksheet does. Massachusetts has no overnight threshold. The worksheet offers three parenting plans — shared, primary residence about 2/3 of the time, and split — and parenting time substantially below 1/3 or between 1/3 and 1/2 is a discretionary deviation (§§ II.D.3-4, IV.B.8-9), so no parenting-time credit is estimated for schedules in between. Monthly inputs are converted to weekly (× 12 ÷ 52, the guidelines' own $450,000 ÷ 52 convention) and the weekly order back to monthly once. The weekly figure is what a Massachusetts order actually states. Child care is collected as each parent's monthly total plus the number of children in care, and the $430/week cap is applied assuming costs are spread evenly across those children. The worksheet applies the cap child by child, so unequal per-child costs can produce a slightly different figure. For split parenting plans, every child is treated as under 18: Table C's reduction for children 18 or older is applied per household on the worksheet, and which household an older child lives in isn't collected. Above the $450,000 cap, the amount shown is the guideline on the first $8,654/week — the minimum presumptive order. Support on the excess is at the court's discretion (§ II.C.2) and is not estimated. Not implemented: Social Security dependency benefits (worksheet lines 2b, 2c and 7c, including the re-run rule for shared and split plans), the hypothetical-order deduction for other children living in a parent's home (§ II.K.3, which requires a second worksheet), children with more than two legal parents (§ II.D.5), attributed or imputed income (§ I.D-E), and the 15 deviation factors in § IV.B. The 40% substantial-hardship presumption (§ IV.C) is flagged but not applied, as on the worksheet. If any of these apply to your case, treat the estimate as a starting point and confirm the figure with an attorney, a mediator, or Massachusetts's official worksheet.

Yes. The figure produced by Massachusetts's Income Shares guideline is presumptive, not mandatory: a court can order a different amount when applying the guideline would be unjust or inappropriate for the specific case, and generally must state its reason on the record. Common grounds include extraordinary medical or educational expenses, a child's special needs, or costs the formula does not capture. Massachusetts's guideline is set out in 2025 Massachusetts Child Support Guidelines (effective December 1, 2025).

You have to file for a modification -- a change in your circumstances does not change what you owe on its own. Massachusetts, like most states, requires a substantial change in circumstances: a significant involuntary income change, a change in the parenting schedule, or a material change in the child's needs. Until a court or the state child support agency issues a new order, the existing amount stays fully enforceable and arrears keep accruing, and a modification is generally not applied retroactively before the date you filed -- so filing promptly matters. In Massachusetts, modifications are handled through Child Support Services — Massachusetts DOR.

Massachusetts publishes it directly: "Child Support Guidelines — Mass.gov". This site's calculator is a fast estimate built on the same published guideline, not a replacement for the official form -- a court filing generally requires the state's own worksheet. The link is in the Massachusetts Resources section on this page.