# 2.4.9 Assessments when a Parent Has Multiple Child Support Cases (Formulas 3 & 4)

## Context

Formula 3 is used to calculate the child support assessment when one or both parents have more than one child support case.

If somebody other than a parent is providing some care for a child and one or both parents have multiple child support cases then formula 4 is used to calculate the assessment for that case.

## Act references

CSA Act section 36 to section 38, section 41, section 42, section 46 to section 48, section 55A to section 55E, section 55HA, section 156

## On this page

Parents can have more than one child support case, that is, they can have children from different relationships in child support assessments with more than one other parent. To recognise a parent's responsibility to support their children in another child support case, one of two separate mechanisms is used. These mechanisms are:

- the multi-case allowance, which is deducted from a parent's adjusted taxable income to reach their child support income at step 1 of the basic formula (CSA Act section 47); and
- the multi-case cap which is a separate calculation for the paying parent worked out at step 8 (section 55E).

For each child, the lesser of the 2 amounts calculated will be the assessed rate of child support. Only one mechanism functions at a time - either the child support is worked out using the income after the deduction of the multi-case allowance, or the child support is worked out according to the multi-case cap on child support.

- Multi-case child costs
- Multi-case allowance
- Multi-case cap
- Multi-case allowance or multi-case cap
- Formula 3-Parents in multiple child support cases
- Formula 4-Multiple child support cases with a non-parent carer
- When child support is payable by or to more than one person

## Multi-case child costs

Both the multi-case cap and the multi-case allowance are calculated using the multi-case costs of the children. The multi-case costs of a child are what it would cost the parent to support the child if all of the children lived with them, based on that parent's income. When calculating the multi-case costs, use the parent's adjusted taxable income less the self-support amount and less the relevant dependent child amount (where appropriate).

To calculate the multi-case child costs of a 'particular child' determine what the costs of all the parent's child support children would be if they were all the same age as this child and divide the costs by the number of child support children.

**Note:** 'all child support children' are all of the parent's children in the child support assessments of the parent for whom you are calculating the multi-case costs.

The approach used to calculate the multi-case costs of a child, although similar, differs from the multiple case method (2.4.6) of calculating the costs of a child. This is because the multi-case costs recognise a parent's responsibility for all their children in all their child support cases, whereas the multiple case method calculates a parent's child support responsibility for the child or children in a case.

**Example:** Jonah has an initial child support income of $20,000 (the adjusted taxable income less the self-support amount). Jonah and Sian have 2 children, Koby aged 14 and Ryan aged 10. Jonah has another child support case with Winfried for child Bran, aged 5. The multi-case child costs for Koby and Ryan would be:

Costs of Koby (14 years old)

= $20,000 × $0.32 (3+ children aged 13+ years from the costs of children tables)

= $6,400 ÷ 3 (divide by number of all child support children)

= $2,133

Costs of Ryan (10 years old)

= $20,000 × $0.27 (3+ children aged 0 - 12 years from the costs of children tables)

= $5,400 ÷ 3 (divide by number of all child support children)

= $1,800

## Multi-case allowance

The multi-case allowance is an allowance deducted from a parent's adjusted taxable income to recognise a parent's responsibility for child support for their children in another child support case (CSA Act section 47).

The multi-case allowance is the sum of the multi-case child costs, excluding the costs of the children of the case to which the assessment relates. That is, the parent has an amount deducted from their income to recognise the costs of supporting the children in their other case or cases. The amount deducted is the total of the multi-case costs of those other children.

**Example:** Julie has children from 3 relationships. Julie and Charlton have 2 children, Jesse and Kevin. Julie and Josef have one child, Patricia. Josef also has an assessment with Hildegard for their children, Debi and Raul. Julie and Ruben have 2 children, Reginald and Jaron.

In calculating Julie's child support income for the assessment for Jesse and Kevin, the multi-case allowance is the multi-case costs of Patricia, Reginald and Jaron.

In calculating Julie's child support income for the assessment for Patricia, the multi-case allowance is the multi-case costs of Jesse, Kevin, Reginald and Jaron. Josef will also have a multi-case allowance, being the multi-case costs of Debi and Raul.

In calculating Julie's child support income for the assessment for Reginald and Jaron, the multi-case allowance is the multi-case costs of Jesse, Kevin and Patricia.

A parent can meet the costs of each child by paying child support, by directly caring for the child or by a combination of the 2. Therefore the multi-case allowance recognises the costs of a child in another case, not the amount of child support payable.

The multi-case allowance is rounded to the nearest dollar (CSA Act section 156).

**Example:** Sam has an initial child support income of $20,000 (the adjusted taxable income less the self-support amount). Sam has no relevant dependent children. Sam and Marisol have 2 children, Moses aged 14 and Adel aged 10. Sam has another child support case with Hiawatha for child Augustine, aged 5. In calculating the assessment for Augustine, the multi-case allowance for Moses and Adel is the total of the multi-case costs for Moses and Adel. The costs are as calculated in the example above.

Child support income for Sam

Multi-case allowance = multi-case costs of Moses + Adel

= $2,133 + $1,800

= $3,933

Initial child support income less the multi-case allowance

= $20,000 − $3,933

= $16,067

## Multi-case cap

The multi-case cap is used to ensure that the parent does not pay more child support for a child than they would if all the children lived in the same household. The cap recognises that the parent may be bearing some of the costs of a child directly through regular or shared care, and is adjusted accordingly. The cap is calculated on a per child basis.

The multi-case cap for each child is the multi-case child costs for the child, less the costs that the parent meets directly through care (their cost percentage).That is:

(100% − cost percentage) × multi-case child costs.

**Example: **If Edward has regular care of child Irene, and therefore a cost percentage of 24% for Irene, and Irene's multi-case child cost is $1,800, then:

Multi-case cap = (100%-24%) × $1,800

= 76% × $1,800 = $1,368

## Multi-case allowance or multi-case cap

The multi-case allowance recognises a parent's responsibility to their other child support children by using an income shares approach. The multi-case cap ensures a parent does not pay more for a child than they would if all children were living in the one household. Both the cap and the allowance are methods of recognising the parent's other obligations, so only one method is needed at any one time.

Only one method will be used to determine the child support amount payable for each child i.e. either the child support amount is worked out using the income after the deduction of the multi-case allowance, or the child support is worked out according to the cap. For each child, the lesser of the 2 amounts calculated will be the assessed rate of child support.

## Formula 3 - Parents in multiple child support cases

When one or both of the parents have at least one other case, and there is no non-parent carer, some variations are made to the basic formula steps to work out the annual rate of child support payable for a child (CSA Act section 36). Additional or changed calculations are made at steps 1, 4, 5, 7 and 8 as explained below.

**Step 1**: To work out each parent's child support income (2.4.7) (section 41), first identify their interim child support income, which is their adjusted taxable income less the self-support amount. Using that income, work out a relevant dependent child (2.4.6) amount (section 46), if required. Deduct that amount from the interim child support income. Then use the interim child support income (less the relevant dependent amount, as required) to calculate the multi-case allowance for each parent with more than one case (section 47). The parent's child support income is their adjusted taxable income less the self-support amount, less any relevant dependent child amounts, and less any relevant multi-case allowance.

**Step 2**: Work out the parents' combined child support income (2.4.7) (section 42).

**Step 3**: Work out each parent's income percentage (2.4.7) (section 55B).

**Step 4**: Work out each parent's percentage of care (2.4.5) for the child (section 48).

**Step 5**: Work out each parent's cost percentage (2.4.5) for the child (section 55C).

**Step 6**: Work out each parent's child support percentage (2.4.5) for the child (section 55D).

**Step 7**: Work out the costs of the child (2.4.6) for the day under section 55HA, calculating the costs for older and younger children separately.

**Step 8**: If a parent has a positive child support percentage under step 6, the annual rate of child support payable by the parent for the child is worked out using the formula:

Child support percentage × cost of the child

The outcome of step 8 will be the child support payable if the parent assessed to transfer child support does not have more than one child support case.

If a parent has more than one child support case and a positive child support percentage under step 6, calculate the multi-case cap for that parent (section 55E):

Multi-case cap = (100% − Parent's cost percentage (2.4.5) for the particular child) × Multi-case child costs for the particular child

The child support payable for the child is the lower of the amounts calculated at step 8, or the multi-case cap.

**Example:** Formula 3 calculations

Vincent and Faith have 2 children, Geraldine aged 14 and Thomas aged 10. Vincent has another child support case with Sigrid for child Honoria, aged 5. Vincent has an adjusted taxable income of $45,000 and Sigrid has an adjusted taxable income of $40,000. Calculate the assessment for Honoria, who lives mostly with Sigrid, for a child support period commencing on 26 August 2008. Vincent has regular care of Honoria, providing care for 75 nights a year. Neither parent has any relevant dependent children.

**Step 1**: Work out each parent's child support income by deducting the self-support amount and a multi-case allowance for any parent with multiple cases from their adjusted taxable income.

Child support income for Vincent

Initial child support income = adjusted taxable income − self-support amount

$45,000 − $18,252

= $26,748

Multi-case costs

Costs of Geraldine (older child):

= $26,748 × $0.32 (3+ children aged 13+ years from the 2008 costs of children table)

= $8,559 ÷ 3 (divide by number of all child support children)

= $2,853

Costs of Thomas (younger child):

= $26,748 × $0.27 (3+ children aged 0 - 12 years from the 2008 costs of children table)

= $7,222 ÷ 3 (divide by number of all child support children)

= $2,407

Multi-case allowance = multi-case costs of Geraldine + Thomas

= $2,853 + $2,407

= $5,260

Vincent's child support income = initial child support income − multi-case allowance

= $26,748 − $5,260

= $21,488

Sigrid has a child support income of $21,748 ($40,000 − $18,252).

**Step 2**: Work out the parents' combined child support income.

$21,488 + $21,748 = $43,236

**Step 3**: Work out each parent's income percentage.

Vincent = $21,488 ÷ $43,236 × 100 = 49.70%

Sigrid = $21,748 ÷ $43,236 × 100 = 50.30%

**Step 4**: Work out each parent's percentage of care for each child.

Vincent has care of Honoria for 75 nights = 20.55%, rounded to a percentage of care of 20%.

Sigrid has care of Honoria for 290 nights = 79.45%, rounded to a percentage of care of 80%.

**Step 5**: Work out each parent's cost percentage for each child by looking up the table in section 55C.

Vincent has a cost percentage of 24%.

Sigrid has a cost percentage of 76%.

**Step 6**: Work out each parent's child support percentage by subtracting their cost percentage for that child from their income percentage.

Vincent = 49.70% − 24% = 25.70%

Sigrid = 50.30% − 76% = −25.70%

(This means that Vincent is responsible for 49.70% of Honoria's costs because they have 49.70% of the combined child support income. As Vincent meets only 24% of the costs through care they need to transfer 25.70% of the costs to Sigrid through child support.)

**Step 7**: Work out the costs of each child.

The combined child support income is $43,236.

From the 2008 costs of children table, the total costs of the child (one child 12 or under) =

$4,654 + ($0.15 for every $1 over $27,378)

$4,654 + ($43,236 − $27,378 = $15,858 × $0.15 = $2,379)

Therefore: $4,654 + $2,379= $7,033

The cost of each child = $7,033.

**Step 8**: Work out the annual rate of child support payable by the parent with a positive child support percentage.

25.70% × $7,033= $1,807

OR use the multi-case cap.

Multi-case cap = (100% − parent's cost percentage for the particular child) × multi-case child costs for the particular child

= (100% − 24%) × $2,407

= 76% × $2,407

= $1,829

As the amount calculated at step 8 ($1,807) is less than the multi-case cap ($1,829), the step 8 amount should be paid.

Vincent is liable to pay Sigrid child support for Honoria of $1,807 (annual rate).

## Formula 4 - Multiple child support cases with a non-parent carer

When one or both of the parents have at least one other case, and one or more non-parent carers has at least 35% percent of care for a child, variations are made to the basic formula steps to work out the annual rate of child support payable for a child (CSA Act section 38). Additional or changed calculations are made at steps 1, 4, 5, 7 and 8 as explained below.

**Step 1**: To work out each parent's child support income (section 41), first identify their interim child support income, which is their adjusted taxable income less the self-support amount. Using that income, work out a relevant dependent child (2.4.6) amount (section 46), if required. Deduct that amount from their interim child support income. Then use the interim child support income (less the relevant dependent amount, as required) to calculate the multi-case allowance for each parent with more than one case (section 47). The parent's child support income, then, is their adjusted taxable income less the self-support amount, less any relevant dependent child amounts, and less any relevant multi-case allowance.

**Step 2**: Work out the parents' combined child support income (2.4.7) (section 42).

**Step 3**: Work out each parent's income percentage (2.4.7) (section 55B).

**Step 4**: Work out each parent's and non-parent carer's percentage of care (2.4.5) for the child (section 48).

**Step 5**: Work out each parent's and non-parent carer's cost percentage (2.4.5) for the child (section 55C).

**Step 6**: Work out each parent's child support percentage (2.4.5) for the child (section 55D).

**Step 7**: Work out the costs of the child (2.4.6) for the day under section 55HA, calculating the costs for older and younger children separately.

**Step 8**: If a parent has a positive child support percentage under step 7, the annual rate of child support payable by the parent for the child for the day is worked out using the formula:

Child support percentage × cost of the child

The outcome of step 8 will be the child support payable if the parent assessed to transfer child support does not have more than one child support case.

If a parent has more than one child support case and a positive child support percentage under step 6, calculate the multi-case cap for that parent (section 55E):

Multi-case cap = (100% − parent's cost percentage (2.4.5) for the particular child) × multi-case child costs for the particular child

The child support payable is the lower of the amount calculated at step 8 or the multi-case cap.

**Example:** Formula 4 calculations

Aliya and Edmund have 2 children, Kristina aged 14 and Harriette aged 10. Aliya has another child support case with Marcus for child Claudia, aged 7. Aliya also has another child Louisa, aged 4, living with them. There is no assessment for Louisa. Aliya has an adjusted taxable income of $45,000 and Edmund has an adjusted taxable income of $70,000.

Calculate the assessment for Kristina and Harriette for a child support period commencing on 26 August 2008. Kristina lives full time with Edmund and Harriette lives full time with a grandparent Ali. Ali has made an application under section 25A for a child support assessment.

**Step 1**: Work out each parent's child support income by deducting the self-support amount, relevant dependent amount (as required) and a multi-case allowance for any parent with multiple cases from their adjusted taxable income.

**Child support income for Aliya**

Initial child support income = adjusted taxable income − self-support amount

= $45,000 − $18,252 = $26,748

Relevant dependent allowance for Louisa

Costs of Louisa (younger child):

= $26,748 × $0.17 (1 child aged 0-12 years from the 2008 costs of children table)

= $4,547

Initial child support income for this case = adjusted taxable income − self-support amount − relevant dependent allowance

= $45,000 − $18,252 − $4,547 = $22,201

Multi-case costs

Costs of older child:

= $22,201 × $0.32 (3+ children aged 13+ years from the 2008 costs of children table)

= $7,104 ÷ 3 (divide by number of all child support children)

= $2,368

Costs of younger child:

= $22,201 × $0.27 (3+ children aged 0-12 years from the 2008 costs of children table)

= $5,994 ÷ 3 (divide by number of all child support children)

= $1,998

Multi-case allowance = multi-case costs of Claudia (younger child)

= $1,998

Child support income = initial child support income (this case) − multi-case allowance

= $22,201 − $1,998

= $20,203

Aliya has a child support income of $20,203.

Edmund has a child support income of $51,748 ($70,000 − $18,252).

**Step 2**: Work out the parents' combined child support income.

$20,203+ $51,748 = $71,951.

**Step 3**: Work out each parent's income percentage.

Aliya = $20,203 ÷ $71,951 × 100 = 28.08%

Edmund = $51,748 ÷ $71,951 × 100 = 71.92%

**Step 4**: Work out each parent's percentage of care for each child.

Aliya has 0% care of Kristina.

Edmund has 100% care of Kristina.

Aliya has 0% care of Harriette.

Edmund has 0% care of Harriette.

(Ali has 100% care of Harriette.)

**Step 5**: Work out each parent's cost percentage for each child by looking up the table in section 55C.

Aliya has a cost percentage of 0% for both Kristina and Harriette.

Edmund has a cost percentage of 100% for Kristina.

Edmund has a cost percentage of 0% for Harriette.

**Step 6**: Work out each parent's child support percentage by subtracting their cost percentage for that child from their income percentage.

Aliya = 28.08% − 0% = 28.08% for both Kristina and Harriette

Edmund for Kristina = 71.92% − 100% = −28.08%

Edmund for Harriette = 71.92% − 0% = 71.92%

(This means that Aliya is responsible for 28.08% of the costs of Kristina and Harriette because they have 28.08% of the combined child support income. As Aliya does not meet any of the costs through care they need to transfer 28.08% of the costs to the carers through child support. Edmund is entitled to receive child support from Aliya for Kristina and is required to pay child support for Harriette.)

**Step 7**: Work out the costs of each child.

The combined child support income is $71,951.

Costs of Kristina (older child):

$15,606 + ($0.25 for every $1 over $54,756) (2 children aged 13+ years from the 2008 costs of children table)

= $15,606 + ($71,951 − $54,756 = $17,195 × $0.25 = $4,299)

= $15,606 + $4,299 = $19,905

= $19,905 ÷ 2

= $9,953

Costs of Harriette (younger child):

$12,868 + ($0.20 for every $1 over $54,756) (2 children aged 12 years or under from the 2008 costs of children table)

= $12,868 + ($71,951 − $54,756 = $17,195 × $0.20 = $3,439)

= $12,868 + $3,439= $16,307.

= $16,307 ÷ 2

= $8,154

**Step 8**: Work out the annual rate of child support payable by the parent with a positive child support percentage.

**Annual Rate payable for Kristina**

Aliya is to pay Edmund: 28.08 % × $9,953= $2,795

OR

Multi-case cap = (100% − parent's cost percentage for the particular child) × multi-case child costs for the particular child

= (100% − 0%) × $2,368

= 100% × $2,368

= $2,368

As the amount calculated at step 8 ($2,795) is more than the multi-case cap ($2,368) the multi-case cap should be paid.

Aliya is liable to pay Edmund child support for Kristina of $2,368 (multi-case cap).

**Annual Rate payable for Harriette**

Both Aliya and Edmund have positive child support percentages for Harriette and therefore both are required to pay child support to Ali.

Aliya is to pay Ali: 28.08 % × $8,154= $2,290

OR

Multi-case cap = (100% − parent's cost percentage for the particular child) × multi-case child costs for the particular child

= (100%-0%) × $1,998

= 100% × $1,998

= $1,998

As the multi-case cap ($1,998) is less than the amount calculated at step 8 ($2,290) then the multi-case cap should be paid.

Aliya is liable to pay Edmund child support for Kristina of $1,998 (annual rate).

Edmund is to pay Ali: 71.92% × $8,154= $5,864

Ali is entitled to receive $1,998 + $5,864 = $7,862

## When child support is payable by or to more than one person

If both parents have a positive child support percentage at step 6 of the formula calculations then both parents pay child support to the non-parent carer or carers (CSA Act section 38(5)).

**Example:** The first parent, Ted, has a child support percentage of 83.47%.

The second parent, Rita, has a child support percentage of 16.53%.

The costs of the child are $1,000.

Both parents are required to pay child support to Valerie, who has full-time care of the child.

Ted will pay $1,000 × 83.47% = $835.

Rita will pay $1,000 × 16.53% = $165.

If one parent, the first parent, has a positive child support percentage at step 6 and the other parent has:

- a negative child support percentage, and
- less than shared care

then the first parent pays child support to the non-parent carer or carers (section 38(5)).

**Example:** The first parent, Arnold, has a child support percentage of 83.47%.

The second parent, Olivia, has regular care of the child and a child support percentage of −7.47% (16.53% − 24%).

The costs of the child are $1,000.

The first parent is required to pay child support to Robert, who has primary care of the child.

Arnold will pay $1,000 × 83.47% = $835.

If one parent, the first parent, has a positive child support percentage at step 6 and the other parent has:

- a negative child support percentage, and
- at least shared care

then the first parent pays child support to the second parent and the non-parent carer (section 38(6)). The child support payable will be divided between the second parent and the non-parent carer by calculating their respective cost percentage as a proportion of their combined cost percentage.

**Example:** The first parent, Marcela, has a child support percentage of 83.47%.

The second parent Frederique, has 37% care of the child (shared care) which is a cost percentage of 29% and a child support percentage of −12.47% (16.53% − 29%).

The non-parent carer, June, has 49% care of the child (shared care) which is a cost percentage of 50%.

The costs of the child are $1,000.

Marcela is liable to pay $1,000 × 83.47% = $835 in total.

Marcela is required to pay child support to Frederique, using Frederique's cost percentage divided by the combined cost percentages of Frederique and June.

Marcela will pay 835 × 29% ÷ (29% + 50%) = $307 to Frederique.

Marcela is required to pay child support to June using June's cost percentage divided by the combined cost percentages of June and Frederique.

Marcela will pay 835 × 50% ÷ (29% + 50%) = $528 to June.

A non-parent carer is not entitled to be paid child support unless they have at least 35% care of the child and they have applied under section 25A (section 40B). If more than one non-parent carer is entitled to receive child support from a parent or both parents, then their share of the entitlement is determined in accordance with section 40A. See 2.4.8 for information about the calculations required when child support is payable to more than one person.

Different rules apply if the minimum annual rate of child support is payable to more than one person. See 2.4.12 for details of the rules that apply, which depend upon the level of care provided by the carer.