How to Update Your Current Income for a Child Support Assessment in Australia
Find out when Services Australia accepts a current-year income estimate for child support and how to submit or update it through your Child Support online account.
AU Australia
Family ~ 5 min read
6 FAQ
Updated 2026-09-29
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If your current adjusted taxable income is at least 15% lower than the income used in your child support assessment, you may be able to lodge an estimate with Services Australia. Sign in to your Child Support online account through myGov, then select Manage circumstances and Estimate income for the current financial year. If you already have an estimate and your income changes, submit a new one as soon as possible; a lower estimate cannot be backdated.
What you need
- A current Child Support assessment and the income amount used in it.
- Your actual income earned so far this financial year and a reasonable estimate of income for the rest of the year, including relevant income sources and other income or allowable deductions.
- The date and reason your income changed.
- A Child Support online account linked to myGov if submitting through the online service. Services Australia may request evidence of your income.
Eligibility
A parent may be able to make a first current-year income estimate when their current adjusted taxable income is at least 15% lower than the income Services Australia uses in the assessment. The relevant income must also have been assessed by the ATO or declared to Child Support, as applicable. Only the person whose income is being estimated can make that estimate. Some assessments involving a child support agreement, a change of assessment decision, a court order or an overseas assessment may not allow this route. A non-parent carer does not need to report income changes for this purpose.
How to do it
- Check the income used in your assessment and whether you can lodge a current-year estimate. If you already have an estimate and your income has changed, prepare a new estimate.
- Sign in to myGov or the myGov app, select Child Support, then choose Manage circumstances and Estimate income for the current financial year.
- Select the relevant financial year, complete the eligibility questions, and enter the reason and date your income changed.
- Enter income earned so far and expected income for the rest of the financial year. Complete the other income and allowable deductions questions that apply to you.
- Review every section, accept the declaration and select Submit. Save the receipt ID. Provide further evidence if Services Australia requests it.
When can you update the income used for child support?
Services Australia generally uses income from an earlier financial year in a child support assessment. If your current adjusted taxable income is at least 15% lower than the income it is using, you may be able to lodge an estimate for the current financial year. The ATO must have assessed the income used in your assessment, or you must have declared it to Child Support if the ATO has not assessed it.
Only you can estimate your own income. An estimate may be unavailable where the assessment involves a child support agreement, a change of assessment decision, a court order or an assessment from another country. If you need to establish an assessment first, see how to apply for a child support assessment.
What income details should you prepare?
For a first estimate that starts after 1 July, the online service asks for two parts: income already earned in the financial year and income expected for the rest of the year, until 30 June. It asks about sources such as wages, lump sum or termination payments, taxable and tax-free pensions or benefits, business income and net capital gains. You also need the reason and date your income changed. Complete the questions about other income and allowable deductions where relevant. Services Australia may ask for evidence.
How do you lodge the update online?
Sign in to myGov or the myGov app and select Child Support. In the online account, choose Manage circumstances → Estimate income for the current financial year. Complete the eligibility questions, enter your year-to-date and expected income, review other income, and check the summary before accepting the declaration and submitting. The service gives you a receipt ID. A saved draft still needs to be completed and submitted.
You can also make an estimate by calling the Child Support Enquiry Line. Services Australia provides the Estimate of income for use in Child Support Assessment form (CS1670), which can be submitted through the Child Support online account or myGov app, or sent by post or fax.
What if your income changes again?
If an estimate is already in place and your income rises or falls, make a new estimate as soon as possible. Services Australia says it cannot backdate a lower estimate and can use an estimate only from the day you tell it. An estimate lasts until the end of the financial year. If your child support period continues into the next financial year, provide a new estimate before the current financial year ends or Services Australia will base the assessment on income from the last financial year.
After the financial year, Services Australia compares the estimate with your actual income. An estimate that was too low may lead to a debt or repayment of an overpayment. Keep your figures as accurate as you can and respond if Services Australia asks for evidence. If your circumstances call for a different assessment decision rather than an income estimate, read about changing an assessment in special circumstances.
Frequently asked questions
Can I lodge an income estimate if my income has fallen by less than 15%?
Services Australia requires current adjusted taxable income to be at least 15% lower than the income used in the assessment for this estimate. A smaller drop alone is not enough to change an assessment through the special-circumstances process.
Can the other parent update my income estimate?
No. Services Australia says only the person whose income is being estimated can make the estimate.
Will a lower estimate change child support for earlier months?
No. Services Australia says it can use an estimate from the day you tell it and cannot backdate a lower estimate. Submit it as soon as possible.
Do I need to update an estimate if my income increases?
Yes. If you already have an estimate and your income goes up or down, you must make a new estimate.
Can I use a paper form instead of completing the online questions?
Services Australia provides form CS1670. You can submit the completed form through your Child Support online account or the myGov app, or send it by post or fax.
What happens after I submit my estimate?
You receive a receipt ID. Services Australia reviews the information and may contact you for more information or evidence. After the financial year, it compares your estimate with your actual income.
Official sources
Services Australia – Child Support online account help: Update current incomeServices Australia – How your income affects your child supportServices Australia – Estimate of income for use in Child Support Assessment form (CS1670)Services Australia – Changing your child support assessment in special circumstancesRelated procedures
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