MA Alimony Plus Child Support Calculator with Tax Consequences

Massachusetts Alimony Plus Child Support Cavanagh Tax Calculator

 

 

The  unique calculator below will do the alimony, child support, and tax calculations required by the Cavanagh decision for contested (1B) divorce cases. The August 2022 Cavanagh v. Cavanagh ruling by the Massachusetts Supreme Judicial Court requires judges in contested divorces to consider the post-tax results of two very different ways of calculating support and alimony. This calculator gives these results, approximating the tax implications, in one step and requires you to do no math. This calculator uses the updated December 1, 2025 child support formulas.

 

Attorney Rueschemeyer provides expert divorce mediation for   Worcester, Boston, Springfield, and all MA locations with online divorce mediation on Zoom.

 

The calculator allows you to download a .pdf that summarizes your inputs and results and provides all the information that Cavanagh requires for judges.

 

According to the Cavanagh decision, judges must do the following in making orders in contested (1B) cases where there might be child support:

 

  1. Calculate alimony first…..Then calculate child support using the parties’ post-alimony incomes.
  2. Calculate child support first. Then calculate alimony…[on family income above $450,000]
  3. Compare the base award and tax consequences of the order that would result from the calculations in step (1) with those of the order that would result from the calculations in step (2), above.

 

The tax calculator uses formulas from the 2025-2026 version of https://goodcalculators.com/us-salary-tax-calculator/massachusetts/ reflecting 2025 changes in tax laws. It gives the most accurate tax estimates for salaried employees with  low, pre-tax deductions such as 401k contributions. It will give less accurate tax estimates for people who make significant 401k contributions, are self-employed, have their own business, have rental income, have investment income, etc.

 

This calculator had a bug for the two weeks leading up to December 9, 2025. In 50-50 parenting time cases, the child support amount it calculated during that period was too high. When in doubt, you can always double check your results against the awkward, complicated state calculator.

 

You can see 4 scenarios of alimony+ child support here.

 

The first set of questions are needed to calculate child support; the 4 questions at the bottom are specifically for calculating alimony.
d)   Which of the following three choices is closest to describing the amount of time the children spend with each parent? Indicate the amount of time that the child spends with each parent by choosing from among 4 choices: about 50% time with each parent, about 1/3 of the time with you and 2/3 of the time with your spouse, about 2/3 of the time with you and 1/3 of the time with your spouse, or (less common) “split” custody, in which different children have primary residence with different parents. Choose the one that is closest to your situation.
  About 67% with Petitioner A and 33% with Petitioner B
  About 50% of the time with each parent
  About 67% with Petitioner B and 33% with Petitioner A
  (Less common) There is more than one child covered by the order, and each parent provides a primary residence for at least one child (different children have different primary residences)
You have indicated that 1 or more children primarily reside with Petitioner A and 1 or more children primarily reside with Petitioner B
 
b-1) Indicate how many children under 18 primarily reside with Petitioner A and how many with Petitioner B:
c-1) Indicate how many children 18 and 23 who receive child support primarily reside with Petitioner A and how many with Petitioner B:
e)   Enter a weekly dollar amount for the following income and expenses:
 
Gross weekly income  Enter the gross weekly income for each parent. Gross weekly income is the total amount BEFORE taxes and other deductions are made from your paycheck.:
(Rare) Weekly Capital Gains or Interest Income (This is $0 for most people.)  If you received assets or property, e.g. a rental property or large stock account, in the division of marital property at divorce, the weekly INCOME generated from this asset should be listed here. This income will be subtracted from your gross weekly income as this income cannot be considered in calculating alimony.:
Health Insurance cost each week  Enter the amount paid by each spouse for family and for individual health care insurance each week.:
Dental/Vision cost each week  Enter the amount paid by each spouse weekly toward the child’s vision or dental insurance. (It can be difficult to separate this out from family vision and dental, since it is typically paid together.):


If you pay child care costs, enter the amount that each parent contributes to the cost for each child. If you do not pay child support for a child, leave it blank:

Child care amount paid for Youngest child:
Child care amount paid for Second Youngest child:
Child care amount paid for Third Youngest child:
Child care amount paid for Fourth Youngest child:
Child care amount paid for Fifth Youngest child:
Weekly alimony or child support paid out to a previous marriage  If either of you pays alimony to a previous spouse or if either of you pays out child support for a child from a previous relationship or marriage, enter the weekly paid out in that person’s column.:


Do you receive a Social Security dependency benefit? (uncommon)

Yes
No
2.b. Enter the total amount of the dependency benefit in the column of the disabled or retired parent  Enter an amount in the column for one parent or the other, not both. A child is entitled to a dependency benefit only through one parent.:
2.c. Enter the amount of the dependency benefit Social Security sends directly to each parent  The total amount from this row 2.c. must equal the amount entered above, in row 2.b.:




Results







1) Calculate alimony first...Then calculate child support using the parties' post-alimony incomes.


This alimony calculation is based on % of the difference between your incomes, which is the percentage you entered (or the default 25.5%, if you made no entry).



2) Calculate child support first. Then calculate alimony on family income above $400,000




3) Compare the base award and tax consequences of the order that would result from the calculations in step (1) with those of the order that would result from the calculations in step (2), above.


Step "1)" Tax Consequences
Gross Annual Income
Annual Alimony based on gross annual income
Annual Child Support based on POST-alimony income
Approximate Annual MA and Federal Taxes based on gross annual income
Approximate annual take-home income after taxes, child support, and alimony

Step "2)" Tax Consequences
Gross Annual Income
Annual Child Support
Annual Alimony based on family income OVER $400,000
Approximate Annual MA and Federal Taxes based on gross annual income
Approximate annual take-home income after taxes, child support, and alimony

Further information


Tax calculations:


Tax calculation formulas come from the 2025-2026 version of: https://goodcalculators.com/us-salary-tax-calculator/massachusetts/


This tax calculator will be most accurate for salaried employees who take the standard deduction. It will be less accurate for people who are self-employed, have their own business, have rental income, have investment income, etc.


This calculator does not include the Child Tax Credit, for children who are 17 or younger at the end of the tax year. These tax credits can be taken by either parent. The separation agreement should specify which parent takes which credits in which years. The amount of this credit was fixed at $2,200 in the 2025 tax bill.


This calculator does not include any Child and Dependent Care Tax Credit, and it does not include any Earned Income Tax Credit (for low- to moderate-income families).



Duration of General Term Alimony





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