IR104 Child Support Income Estimate 2027: Fill In Online

What is IR104 (child support income estimate 2027)?

New Zealand child support is normally worked out from income figures Inland Revenue already holds, usually from an earlier year. If your income has dropped, for example because you lost your job, cut your hours or stopped working for a while, that can mean paying (or being assessed on) more than your current income supports. An income estimate lets your child support be based on what you expect to earn this year instead.

The IR104 is the paper version of that estimate for the child support year 1 April 2026 to 31 March 2027. Inland Revenue says both paying parents and receiving carers can estimate, but only if they expect their total income for the year to be at least 15% lower than the amount on their assessment. After the year ends, Inland Revenue compares your estimate with what you actually earned and squares up. If you earned more than you estimated, you may have extra child support to pay, and you'll have 30 days to pay it.

FileIt fills in the February 2026 edition of the IR104 for you. It prints each amount in the form's separate dollars and cents boxes, fills in the 'last month' and 'this month' names from the month you're completing it, puts the currency code beside each overseas amount and places 8-digit IRD numbers in the right boxes. The finished PDF is saved to your FileIt vault, ready to sign and post.

Who fills it: A paying parent or receiving carer (not a non-parent carer)
When: You expect this year's total income to be at least 15% lower than on your assessment
Year covered: 1 April 2026 to 31 March 2027 (child support year 2027)
Sent to: Child Support, PO Box 39010, Wellington Mail Centre, Lower Hutt 5045
Online option: myIR: 'Apply for a child support income estimation'
Edition: IR104 February 2026

Who needs to fill out IR104 (child support income estimate 2027)?

Paying parents whose income has dropped by 15% or more compared with the income used in their child support assessment.
Receiving carers whose income has dropped by 15% or more, since their income is also used in the formula.
Anyone who has already estimated this year and needs to change the estimate.
Parents with overseas income, who give it in the currency they receive it in.

When to use IR104 (child support income estimate 2027)

During the child support year 1 April 2026 to 31 March 2027, when your income is expected to be at least 15% lower than on your assessment.
Before 1 May 2026, you estimate the whole year. On or after 1 May 2026, you give your income so far and an estimate for the rest of the year.
If you estimated less than 3 months ago, Inland Revenue says your annualised estimate must have changed by at least $500 for a new one to be accepted.
If your income goes back up, the declaration says you should cancel the estimate or re-estimate before 31 March 2027.

What you need before you start

Your IRD number, name, address and contact details.
Your New Zealand taxable income from 1 April 2026 to the end of last month (payslips help), leaving out superannuation fund income such as KiwiSaver.
A realistic estimate of what you'll receive from the 1st of this month to 31 March 2027.
Any overseas income, in the currency you receive it in, and that currency's code (such as AUD).
Inland Revenue's factsheet IR151, 'Child support - estimating your income', which the form asks you to read first.

What’s on IR104 (child support income estimate 2027)

The 2026 edition has 3 pages. FileIt asks for it in 6 parts, and it is signed by Parent (paying parent or receiving carer):

Your detailsParent (paying parent or receiving carer)
Which period you're estimatingParent (paying parent or receiving carer)
New Zealand incomeParent (paying parent or receiving carer)
First overseas currencyParent (paying parent or receiving carer)
Second overseas currencyParent (paying parent or receiving carer)
DeclarationParent (paying parent or receiving carer)

How to fill out IR104 (child support income estimate 2027), step by step

1 Your details

Enter your New Zealand IRD number, tick your title and give your name, address, phone numbers and email. The form notes that 8-digit IRD numbers start in the second box; FileIt places them there for you.

2 Section 1 - New Zealand income

Complete one option. Before 1 May 2026, estimate your income for 1 April 2026 to 31 March 2027. On or after 1 May 2026, give your year-to-date income from 1 April 2026 to the last day of last month, and your estimated income from the 1st of this month to 31 March 2027. For no income, enter $0.00. Include all taxable income except superannuation fund income such as KiwiSaver; tax losses from earlier years can't reduce it.

3 Section 2 - Overseas income

If you have income from another country, give it in the currency you receive it in, with that currency's code, using the same option as for New Zealand income. There's room for two currencies; for a third, attach a separate sheet with your name and IRD number at the top. Income from a country without income tax still counts.

4 Declaration

Sign and date the declaration. It says you choose to use this estimate for your 2027 child support assessment, that you should cancel or re-estimate before 31 March 2027 if your expected income changes, and that the information is true and correct.

Common mistakes to avoid

Estimating when your income isn't at least 15% lower than on your assessment. Inland Revenue can't accept it.
Choosing the wrong option. After 1 May 2026, give your year-to-date income and an estimate for the rest of the year, not a whole-year figure.
Including KiwiSaver or other superannuation fund income, or subtracting tax losses from earlier years.
Converting overseas income to New Zealand dollars yourself. Give it in the currency you receive it in.
Underestimating. After 31 March 2027 Inland Revenue compares your estimate with your actual income, and you may have extra child support to pay within 30 days.
Forgetting to re-estimate or cancel if your income goes back up.

After you fill it out

Print the form, sign and date it, and post it to Child Support, PO Box 39010, Wellington Mail Centre, Lower Hutt 5045.

Inland Revenue may ask for proof, such as payslips. If they accept your estimate, they reassess your child support and send you a new letter. If they can't, they write to explain why.

After 31 March 2027 they square up, using whichever is lower of your actual income or the income originally assessed. Keep this form and your payslips in your FileIt vault for that.

Fill out IR104 (child support income estimate 2027) online with FileIt

Pick the person. Choose someone from People and FileIt fills in their name, date of birth, address and other details it already knows.
Answer plain-language questions. One part of the form at a time, with the official help text beside each question — 61 fields in all. Your answers save as you go.
Check the live preview. Watch your answers land on the real Inland Revenue (Te Tari Taake) form, and let FileIt do any worksheet arithmetic.
Generate the official PDF. FileIt prints your answers into the agency’s own PDF and files it in that person’s folder in your vault. Sign it, or send it for e-signature.

FileIt fills the form — it never files or submits anything for you. Deliver the finished form to whoever asked for it, the way the form’s instructions say.

Start IR104 (child support income estimate 2027) now — it’s free

IR104 (child support income estimate 2027): frequently asked questions

Can I reduce my child support if my income drops?

Yes, if you expect your total income for the year to be at least 15% lower than the income on your assessment. You can estimate your income in myIR or on the IR104, and Inland Revenue reassesses your child support if it accepts the estimate.

Who can estimate their income for child support?

Inland Revenue says both paying parents and receiving carers can. Non-parent carers can't, because their income isn't used in the child support formula.

What happens if I underestimate my income?

After the year ends on 31 March, Inland Revenue compares your estimate with what you actually earned. If you earned more, you may have a bill for the extra child support, with 30 days to pay it.

What counts as income on the IR104?

All your taxable income, except income from a superannuation fund such as KiwiSaver. Tax losses from a previous year can't reduce it. Overseas income counts too, given in the currency you receive it in.

Where do I send the IR104?

Post it to Child Support, PO Box 39010, Wellington Mail Centre, Lower Hutt 5045. You can also estimate online in myIR.

Can I fill in the IR104 online?

Yes. FileIt's guided questions print your answers into Inland Revenue's official IR104 PDF, which is saved to your vault. You then sign it and post it.

Official sources

Blank form (PDF), published by Inland Revenue (Te Tari Taake): https://www.ird.govt.nz/-/media/project/ir/home/documents/forms-and-guides/ir100---ir199/ir104/ir104.pdf
Official instructions and guidance: https://www.ird.govt.nz/child-support/changes-to-family-job-income/when-your-income-drops/estimate
Edition shown on this page: IR104 February 2026 (child support year 1 April 2026 - 31 March 2027) (checked 2026-09-28).

FileIt is not affiliated with or endorsed by Inland Revenue (Te Tari Taake) or any government. This page explains the form in general terms and is not legal, tax or immigration advice. Always read the official instructions, and check that you are using the edition the recipient accepts. Page last reviewed 2026-09-28.