Child Support Calculator Australia 2026

Which child support calculator should I use in 2026?

Use the Child support estimator available through Online estimators on the Services Australia website. A separate Child support care estimator helps you work out the care percentage to use. The amount estimator does not include family assistance payments, and it cannot cover every family situation.

The official estimator excludes cases where a parent pays or receives child support in more than one case, and cases involving a non-parent carer. If either applies, bring your existing assessments to your consultation. NS Legal will identify the relevant calculation pathway and the information needed for your circumstances.

The basic formula has eight steps. It works out each parent’s child support income after applicable deductions, their share of the combined income, and the costs they meet through care. The remaining positive child support percentage is applied to the costs of the children. This is why a percentage of your salary alone cannot establish the amount payable.

What do I enter at each step of the official estimator, and how do I read the result?

The Child Support Estimator runs in four steps (Parents, Income, Children and Results) and is linked from the Services Australia Online estimators page:

1. 01Parents: how many children the estimate is for, whether each parent has other dependent children and how many, and whether either parent has two or more child support assessments.
2. 02Income: each parent’s taxable income, reportable fringe benefits, total net investment loss, specified tax-free pensions and benefits, target foreign income and reportable superannuation contributions for the last completed financial year (1 July to 30 June), and whether either parent received an Income Support Payment in that year.
3. 03Children: each child’s date of birth and the nights of care you provide, entered per week, fortnight, month or year.

If you do not know the number of nights, work out the care percentage first with the Child support care estimator, using a recurring pattern or individual dates.

The Results step shows an estimate of the child support you pay or receive. It does not include family assistance payments. The estimate is only as good as the information entered: if any detail is wrong, the result will be wrong, and Services Australia says an estimate should not be relied on for future income or payments. The information you enter is not retained. NS Legal can compare your estimate line by line with your assessment notice and show whether a difference comes from income, care or other children.

What income should I enter?

Start with adjusted taxable income, rather than the amount deposited into your bank account. For child support, this can include taxable income, reportable fringe benefits and superannuation contributions, net investment losses, specified tax-free pensions or benefits, and relevant foreign income.

Services Australia generally uses income for the financial year ending before the current child support period. Your latest payslip may therefore show a different position from the income on your assessment notice. Have your tax information, current income records and assessment available together.

NS Legal will help you identify the income components in issue and prepare supporting documents, whether you are concerned about your own changed income or figures used for the other parent.

How do care arrangements and other children affect the estimate?

Care affects the share of a child’s costs each parent is treated as meeting directly. Services Australia usually bases care on the actual arrangements. Its care estimator lets you enter recurring overnight care or individual dates and calculates nights and a care percentage.

If you disagree about care, supporting evidence may include a calendar, school records, or parenting orders with evidence of how they operate. Keep records for each child separately where their arrangements differ. We can organise that evidence and address the related parenting arrangements with you.

Other relevant dependent children may lead to an income deduction, subject to eligibility. Children already included in another child support assessment are dealt with differently. Multiple assessments involve additional allowances and a cap; entering only the children from one relationship may miss those adjustments.

Is an estimate the same as an assessment or private agreement?

No. Services Australia makes the administrative assessment, while an estimate depends on the information you supply. Private agreements have their own requirements. A limited child support agreement needs an assessment already in place and payments at least equal to its annual rate. A binding child support agreement requires each party to receive independent legal advice.

Private Collect describes how payments move directly between parents. It does not determine a new payment amount: the assessment, accepted agreement or registered court order supplies that amount. Keep the payment records and the document setting the obligation together.

NS Legal can advise on agreement terms and negotiate how payments and agreed expenses will be handled. Where discussion could help resolve the arrangements, our family mediation service can support that process.

How do I update child support when income or care changes?

You may be eligible to lodge a current income estimate if your adjusted taxable income is at least 15% below the income used in the assessment. Income declaration requirements also apply, and an agreement or court order may affect eligibility. You can submit an estimate through your Child Support account linked to myGov. It generally applies from when you notify Services Australia, so delaying may leave the previous income in use.

Report care changes promptly. Notification within 28 days generally allows the assessment to be adjusted from the change date. With late notification, increased care may only count from the notification date. Record what changed, when it changed and when you reported it.

We can prepare the supporting information and distinguish an income update from a care dispute, so your request addresses the decision that needs to change.

What should I bring to a child support consultation?

Bring the assessment notice, tax and income records, a care calendar and any existing agreement. Include correspondence about changes and a short chronology of what you reported. If you are also negotiating a property settlement, bring that proposal so we can discuss the arrangements together.

Book through our contact page or call +61 2 8251 1999. Our Sydney office is at Level 7/263 Clarence St, Sydney NSW 2000. Arrangements for a first consultation are explained when you book.

Compiled from official sources; updated 29 October 2026.