Find answers to common questions about child support in Australia.
Child support is calculated using the official 8-step formula from Services Australia. It considers both parents' incomes, the cost of raising children (based on age), care percentages, and any relevant dependents.
50/50 care does not automatically mean no child support. Even when time is shared equally, the system looks at each parent's income to reflect how the children would have been supported if both parents were still together, where income is effectively pooled and the higher earner contributes more. After separation, this principle is maintained by balancing financial capacity across two households, so if one parent earns significantly more, they may still pay child support to help ensure the children experience a more consistent standard of living in both homes.
Child support uses your Adjusted Taxable Income (ATI), which includes taxable income, reportable fringe benefits, target foreign income, certain tax-free pensions, net investment losses, and reportable superannuation contributions.
The Self-Support Amount (SSA) is a fixed amount set aside from each parent's income to cover their own basic living expenses before child support is calculated. It is based on one-third of Male Total Average Weekly Earnings (MTAWE) and is updated each year. In 2026, this is $31,046 per year. This amount is deducted from a parent's Adjusted Taxable Income (ATI) to determine their child support income, ensuring that only income above a basic self-support level is used in the formula. In practical terms, it means the system assumes each parent must first meet their own essential needs, and only their remaining income is considered available to contribute to the costs of raising their children.
The impact of additional children depends on which parent is assessed to contribute financially for each child. The formula determines this by comparing both parents' incomes and levels of care. For each child, it works out who is meeting their share of costs through care and who needs to contribute financially, so the effect of more children depends on how income and care are distributed between the parents.
Australian child support uses five main care levels: Below Regular Care, Regular Care, Shared Care, Primary Care, and Above Primary Care. These are based on the number of nights a child spends with each parent over a year. The level matters because it affects the cost percentage credited to each parent, which can increase or reduce the amount of child support payable.
Relevant dependents are other children you support who are not part of this child support case. Each relevant dependent reduces your child support income by an amount calculated using the Costs of Children table based on your income and the ages and number of dependent children.
This calculator applies the exact child support formula, including all six formula types, using the current 2026 rates and rules used by Services Australia. It fully replicates how an official assessment is calculated, with a transparent, step-by-step breakdown of each stage. Unlike simplified tools, it accounts for the full structure of the scheme, including income, care, and multi-case interactions, delivering a level of accuracy that closely matches, and in many cases exceeds, the official calculator.
Child support is automatically reassessed whenever key inputs change, particularly when new tax returns are lodged, income estimates are updated, or care arrangements change. While there is usually an annual update based on tax data, assessments can be adjusted at any time during the year as new information becomes available.
A Change of Assessment is a process where Services Australia reviews a child support assessment when the standard formula does not fully account for a family's circumstances. It allows adjustments for factors beyond income and care, such as additional costs, financial resources not reflected in taxable income, or situations where the formula does not properly reflect the actual costs each parent is meeting to support the children.
You can apply when special circumstances mean the standard formula doesn't reflect your true situation. Common reasons include: the other parent has hidden income, you have high travel costs to see your children, or a property settlement affects your capacity to pay.
The legislation sets out 10 specific grounds: 1. The costs of maintaining the child are significantly affected by the high costs of spending time with or communicating with the child 2. The costs of maintaining the child are significantly affected by the special needs of the child 3. The costs of maintaining the child are significantly affected by the high costs of educating or training the child in the way both parents intended 4. The child has income, earning capacity, property, or financial resources that should be taken into account 5. A parent has paid money or transferred property for the benefit of the child 6. The costs of maintaining the child are significantly affected by the high costs of child care 7. A parent's capacity to support the child is significantly affected by their income, earning capacity, property, or financial resources 8A. A parent has income, earning capacity, property, or financial resources not properly reflected in the assessment 8B. A parent's earning capacity is not properly reflected due to their reduced income or underemployment 9. A parent has a legal duty to maintain another person or child 10. A parent has responsibility for the care of another child or person in their household
There is no fixed timeframe set in the legislation. Most applications are decided within several weeks, but more complex cases, particularly those involving multiple issues or detailed financial review, can take longer depending on the information required and the process followed.
Evidence depends on the reason you're applying. Common documents include tax returns, receipts, medical reports, payslips, bank statements, and evidence of the other parent's lifestyle or assets.
The other parent cannot object to the application itself. They are invited to provide information and evidence as part of the process before a decision is made. After the decision, both parents have the right to formally object and seek a review if they disagree with the outcome.
Services Australia will review your application, may request additional information from both parents, and may contact each party to clarify their circumstances. A Registrar will then make a decision based on all the information and evidence provided.
Yes. If you disagree with the decision, you can lodge an objection with Services Australia within 28 days. If you are not satisfied with the objection outcome, you can then apply to the Administrative Review Tribunal (ART) for an independent review. Legal advice can help you understand your options.
You can request a Change of Assessment through Services Australia. Our inquiry form connects you with family law professionals who can advise on your eligibility and help prepare your application.
After submitting your details, you can typically expect to be contacted by a family law professional within 1–2 business days, depending on availability and your circumstances.
Yes. Your personal and financial information is handled securely and used only for the purpose of assessing your enquiry. It may be shared with relevant legal professionals so they can review your situation and respond appropriately.
Costs vary depending on the lawyer and the complexity of your situation. Some family lawyers offer an initial consultation at a fixed fee or no cost, while ongoing advice is priced based on the work required and the specifics of your matter.
A lawyer can help with Change of Assessment applications, objections, ART reviews, binding child support agreements, and cases involving hidden income or complex financial structures.
A lawyer is not required, but professional advice can help strengthen your case, especially for complex matters like Reason 8A (hidden income) or when the other parent has legal representation.
Split care occurs when each parent has one or more of the children in their care. A separate assessment is made for the children in each parent's care, taking into account both parents' incomes and care levels. These amounts are then offset against each other, resulting in a single net amount payable between the parents.
Care is calculated over the entire year, including school holidays. If you have your children during school holidays, these nights are added to your total annual care calculation.
If the other parent does not follow the agreed care arrangement, your child support assessment can still be updated to reflect what is actually happening. Services Australia generally considers the real pattern of care in practice, not just what was agreed or ordered, especially if the change is ongoing. You may need to provide evidence such as a care diary, messages between parents, or school records. Small or short-term variations usually do not affect your assessment, but consistent and ongoing changes in care can be taken into account and may result in your child support amount being adjusted.
You should report a change in care to Services Australia as soon as it happens. If you notify them within 28 days, the change can be applied from the date the care actually changed. If you report it later than 28 days, the parent whose care has decreased will still have their reduction applied from the date of event, but the parent whose care has increased will usually only have that increase recognised from the date they notified Services Australia.
A below regular care determination is a decision made when a parent who was previously assessed to have at least regular care (14% or more) ends up having less than 14% care, or no care at all, even though the child is still being made available to them. It applies where there has been a clear change in the pattern of care over time and the other parent notifies the change within a reasonable period. In these cases, the child support assessment can be updated to reflect that the parent has below regular care, and the change can be backdated to when the care actually stopped, even if this is more than 28 days before notification, provided the delay in reporting was reasonable in the circumstances.
Apply when the standard formula produces an unfair result due to special circumstances, such as: the other parent has unreported income, you have very high contact costs, or your child has special medical needs.
Yes. You can list multiple reasons in one application. Many applicants combine Reason 8A (hidden income) with other financial reasons to present a complete picture of their situation.
The lawyer will review your calculation, discuss your situation, and advise whether you have grounds for a Change of Assessment. They can help you prepare and lodge your application.
All 10 reasons are equally valid, but some are more common and have higher success rates. Reasons 8A (hidden income) and 1 (high contact costs) are frequently applied and have established precedents.
A binding child support agreement allows parents to set any amount of child support, including zero, regardless of what the formula would produce. Both parties must receive independent legal advice from a solicitor before signing, and once accepted by Services Australia, it's difficult to change or terminate. Binding agreements can only be ended by mutual written agreement, a subsequent binding agreement, or a court order (except in exceptional circumstances causing hardship). A limited child support agreement is simpler and doesn't require legal advice, but the agreed amount must be at least equal to the formula assessment on the day it's submitted for acceptance. Limited agreements offer less permanence: either party can terminate after 3 years by giving written notice (takes effect 28 days after the Registrar receives it), or either party can terminate within 60 days if the notional assessment changes by more than 15% due to circumstances not contemplated in the agreement (such as unexpected care changes or income shifts not covered by clauses in the agreement).
Yes. Parents can agree to a private collect arrangement, where Services Australia calculates the amount but the parents manage payments directly. If payments fall behind, the payee can opt in to have Services Australia collect on their behalf — and can include any missed payments from the three months prior to the application as arrears. Alternatively, a binding child support agreement can set a custom amount outside the standard formula entirely.
If child support is managed through Services Australia and payments are missed, Services Australia can take enforcement action. This includes garnishing wages or bank accounts, intercepting tax refunds, suspending passports, and in serious cases, referring the matter for legal action. If you have a private arrangement, you may need to apply for Services Australia to collect on your behalf, or seek a court order.
Child support generally ends when a child turns 18. If the child is still in secondary school at 18, support continues until they finish school or turn 18, whichever is later — but only up to the end of the school year in which they turn 18. Support can continue beyond 18 by agreement or court order in limited circumstances, such as a child with a disability.
Child support received by the payee is assessed under the Maintenance Income Test (MIT), which reduces FTB Part A by 50 cents for every dollar of maintenance income above the Maintenance Income Free Area (MIFA) — but only down to the base rate, not below it. To receive above the base rate of FTB-A, payees must also satisfy the Maintenance Action Test (MAT) by taking reasonable steps to obtain a child support assessment. If the MAT is not met and no exemption applies, FTB-A is reduced to the base rate for that child. For payees on a private collect arrangement, Centrelink deems the full assessed amount to have been received, even if the payer didn't actually pay. For payers, child support payments may be deducted from their Adjusted Taxable Income as Deductible Child Maintenance Expenditure (DCME), which can increase their FTB entitlement.
This only applies if Services Australia is collecting child support on your behalf (agency collect). In that case, you can choose how your FTB Part A is estimated: the entitlement method bases it on your full assessed amount, while the disbursement method bases it on what was actually paid out each month. If the other parent is paying irregularly or not at all, the disbursement method can result in a higher FTB-A rate during those periods. If you are on a private collect arrangement, you have no choice — the entitlement method always applies and you are deemed to have received your full assessed amount regardless of what was actually paid. If underpayment is ongoing, switching to agency collect may be worth considering.
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