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Estimation of income for child support


If you've registered for online services, you can complete your income estimation online. The form will pre-populate with your personal details.

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About this service

This service will allow you to estimate your taxable income for your child support assessment. It is the same as completing the Estimate of income for child support assessment (IR104) form.

When to use this service

Use this service if you pay child support during the tax year (1st April and 31st March).

  • The income you estimate must be at least 15% lower than your taxable income used to work out your current child support assessment.
  • Another estimate of taxable income can be made before or during the child support year, but not after, by completing another copy of this form or applying in writing.

This form will take about ten minutes to complete.

What you will need

For this income estimation to be accepted, as well as submitting "on-line estimation", you will also need to send us proof of your income, this can be either:

  • two new payslips showing your reduced income, or
  • a letter from your employer or accountant advising your reduced income details, or if you are on a benefit then all you need to do is provide your WINZ number.
After you finish

After we receive your application we will reassess your child support payments.

If your income changes again during the year you can submit another of these forms to ensure your payments continue to be assessed correctly.

This service may require you to send confidential information to Inland Revenue so it is located on a secure part of our website to prevent unauthorised interception. If you are unable to access this service, your browser and/or firewall settings may need updating.

Inland Revenue takes online security very seriously. We have systems in place to protect the information you provide us, and regularly update our standards and technology to provide protection for your personal information.

You play an important role in protecting your information by taking basic precautions to protect your computer and data. You should keep your computer secure, only deal online with people and organisations you know and trust, and check that your personal information travels across the internet on secure connections.

There are many resources about computer security (such as websites, books and magazines) that can help guide you on what security precautions are appropriate for your situation.