When two parents have more than one child, it is possible for each parent to have the primary physical custody of at least one of the children. This is called “split custody.”

To compute child support for split custody, you have to take several steps. You will use the child support guidelines to see what each parent owes the other. The parent who owes more will then pay what they owe, minus the amount that the other parent owes. This article shows the steps.

What steps do I take?

Follow these steps to determine the required child support payment of a parent in cases of split custody. After each step, we give an example. 

Step 1: Determine the “adjusted actual income” of each parent.

This includes all of the parent’s income, minus certain payments that parent makes for other support obligations. For more information, see the article on calculating child support. 

Example: 

• Parent 1 makes $40,000 each year, and pays no other child support, alimony, etc.
• Parent 2 makes $70,000 each year, and actually pays $10,000 each year in other child support to another parent. 
• Parent 1 and Parent 2 have three children together.
  • Parent 1 cares for two of them.
  • Parent 2 cares for one.
• Parent 1’s adjusted actual income is $3,333.33 per month. ($40,000/12 months=$3,333.33)
• Parent 2’s adjusted actual income is $5,000 per month. ($70,000 - $10,000 = $60,000; $60,000/12 months=$5,000)

Step 2: Add the adjusted actual incomes of both parents together. This gives the “combined adjusted actual income.”

Example: The combined adjusted actual income, for Parent 1 and Parent 2, is $8,333.33 per month.

• Parent 1's adjusted actual income is $3,333.33.
• Parent 2's adjusted actual income is $5,000.
• $3,333.33 + $5,000 = $8,333.33

Step 3: For each parent, compute that parent’s percentage share of the combined income. To do this, divide that parent’s adjusted actual income by the combined adjusted actual income.

Example: Parent 1’s percentage share of the combined income is 40%. Parent 2’s percentage share of the combined income is 60%. 

• Parent 1’s percentage share of the combined income is 40%.
  • Parent 1's adjusted actual income is $3,333.33.
  • The combined adjusted income is $8,333.33.
  • Divide Parent 1's adjusted actual income by the combined adjusted actual income.
    • $3,333.33/$8,333.33= 0.3999
  • Multiply this number by 100 to get a percentage.
    • 0.3999 x 100 = 39.99%
  • Round up to nearest whole number.
    • 39.99% rounds up to 40%

• Parent 2’s percentage share of the combined income is 60%.
  • Parent 2's adjusted actual income is $5,000
  • The combined adjusted income is $8,333.33.
  • Divide Parent 2's adjusted actual income by the combined adjusted actual income.
    • $5,000/$8,333.33= 0.60
  • Multiply this number by 100 to get a percentage.
    • 0.60 x 100 = 60%

Step 4: For each parent, look up the “basic support obligation” using the number of children in that parent’s primary custody and “combined adjusted actual income” from Step 2. The basic support obligation is a set amount related to the cost of supporting the children.

• Refer to the table in Maryland Code, Family Law, section 12-204.
• For an income amount between two rows in the table, use the larger amount.
• For higher income levels above what is included in the table, talk to an attorney.

Example:  The basic support obligation that Parent 1 needs is $1,768 (2 children, $8,333.33/month). The basic support obligation that Parent 2 needs is $1,240 (1 child, $8,333.33/month)

Step 5: Calculate the amount each parent owes the other.

1. To determine how much Parent 1 owes to Parent 2, multiply the basic support obligation that Parent 2 should receive by Parent 1’s percentage share of the combined income.
2. To determine how much Parent 2 owes to Parent 1, multiply the basic support obligation that Parent 1 should receive by Parent 2’s percentage share of the combined income.

Example:  Parent 1 owes $496/month to Parent 2. Parent 2 owes $1,060.80/month to Parent 1.

• Parent 1
  • Parent 2's basic support obligation is $1,240 (see Step 4).
  • Parent 1's percentage share of the combined income is 40% (see Step 3).
  • Multiply Parent 2's basic support obligation by Parent 1's percentage share.
    • $1,240 x 0.40 (note that 40% = 0.40) = $496

• Parent 2
  • Parent 1's basic support obligation is $1,768 (see Step 4).
  • Parent 2's percentage share of the combined income is 60% (see Step 3).
  • Multiply Parent 1's basic support obligation by Parent 2's percentage share.
    • $1,768 x 0.60 (note that 60% = 0.60) = $1,060.80

Step 6: The parent owing the greater amount would pay the difference between the two amounts to the other parent.

Example: Parent 2 should pay $513.60/month to Parent 1.

• Parent 2 owes Parent 1 $1,060.80
• Parent 1 owes Parent 2 $496
• $1,060.80 - $496 = $564.80

Read the case: Tannehill v. Tannehill, 88 Md. App. 4 (Court of Special Appeals 1991)

Calculating child support in split custody cases can be complex, and you may wish to consult with an attorney. Most circuit courts in Maryland have family law assistance programs, including self-help centers staffed with attorneys who provide walk-in services. Information is available on the Maryland Courts website. The People's Law Library has more information about getting help from an attorney, including free and low-cost options.