70/30 Care and Child Support in Australia

A 70/30 care split does reduce child support compared to sole care, but in most cases the lower-care parent still pays. The 30% care percentage sits below the 35% shared care threshold — which means full cost offsets do not apply, and the income difference between parents continues to drive most of the result.

Use the child support calculator to estimate your specific case.

Does 70/30 Care Reduce Child Support?

Yes — but not as much as many parents expect.

At 30% overnight care, the lower-care parent is in the 14–34% care band under the Services Australia formula. This band applies a partial cost offset, but the full shared care offset (which kicks in at 35%) does not apply.

The income difference between parents remains the primary driver of the assessment. If the lower-care parent earns significantly more than the higher-care parent, they will almost certainly still pay meaningful child support even with 30% overnight care.

Why 70/30 Is Still Usually a Paying Case

The formula works in two stages:

1. It calculates each parent's share of combined child support income
2. It applies a costs of care offset based on the number of nights

At 30% care, the offset is real but limited. Here is why the lower-care parent usually still pays:

• The costs of raising a child at 30% care (roughly 109–127 nights per year) are genuine but lower than at 35%+
• The income-share component — the gap between what each parent earns — typically outweighs the care offset for most income combinations
• The formula is specifically designed not to reduce payments to zero simply because one parent has regular overnights below the 35% line

The most common surprise for parents in a 70/30 arrangement is that jumping to 35% overnight care creates a much larger reduction in liability than the difference in care percentage would suggest.

Example: One Child, 70/30 Care

• Parent A (lower care): $95,000 adjusted taxable income, 30% care (109 nights)
• Parent B (higher care): $50,000 adjusted taxable income, 70% care (256 nights)
• One child aged 6

At 30% care, Parent A sits in the below-threshold band. The formula calculates each parent's income percentage of the combined child support income, then applies a costs of care contribution based on their care percentage.

Because Parent A's income share exceeds their care cost contribution, they pay the difference to Parent B. At 35% care (128 nights), the full shared care offset would apply, and the liability would drop further.

Example: Two Children, 70/30 Care

With two children, the base cost figure from the Costs of the Children table is higher, which increases the assessment before care offsets are applied. The income gap between parents is amplified.

A parent at 30% care of two children, earning notably more than the other parent, can face a substantial annual payment even though they have regular, meaningful care. The 70/30 split does reduce what they would otherwise pay — it just does not bring the figure close to zero.

How Holidays Can Change the Annual Night Count

Care percentages are calculated over 365 nights per year. Holiday arrangements can shift the percentage noticeably:

• If the lower-care parent has the child for most school holidays (e.g. 4 weeks over summer, 2 weeks mid-year), this adds around 42 nights — enough to push 30% care close to or above the 35% threshold
• Conversely, if school holidays are primarily with the higher-care parent, the lower-care parent may drop below 30%

It is worth calculating the annual night total for your actual schedule — not just the fortnightly pattern — before making assumptions about where you sit in the formula. Use the care percentage calculator to convert your schedule to a percentage.

Where Parents Misread 70/30 Outcomes

“I have the kids nearly a third of the time — that should mean I pay much less.”
The formula does acknowledge 30% care, but the reduction from the sole-care baseline is partial, not proportional. Paying one-third less than a sole-care assessment is a reasonable rough estimate, but income differences can make the gap smaller or larger.

“If I get a few more nights, I'll be at 35% and my payments will drop a lot.”
This is often true — the 35% threshold genuinely matters in the formula. But adding nights must reflect a genuine change in the parenting arrangement, not a theoretical one. Services Australia assesses actual care.

“My 70/30 arrangement means the other parent is responsible for 70% of costs.”
The formula does not split costs in the same proportion as care. It looks at each parent's income share and their care contribution, then calculates what balances the two.

When to Compare Against a Formal Assessment

The calculator gives an estimate based on standard formula inputs. A formal Services Australia assessment may differ if:

• Either parent's income is irregular, disputed, or assessed differently by Services Australia
• There is a change of assessment application in progress
• The care arrangement is new or contested
• There are other children or other cases involved

→ See estimate vs formal assessment for a full comparison of when they diverge.

Frequently Asked Questions

This page provides general information about the child support formula in Australia. It is not legal advice. If your care arrangements are disputed or your case involves non-standard income, consider seeking advice from a family lawyer.