IR3 vs Automatic Assessment 2025-26 & 2026-27 — When Must You File an IR3? (IRD)

If IRD will auto-assess you anyway, do you actually need to file an IR3? For most PAYE earners the answer is no — but for several specific income types, filing an IR3 is compulsory, and missing it exposes you to penalties even if IRD’s automatic assessment looks fine on its face.

This guide covers the 2025-26 tax year (1 Apr 2025 – 31 Mar 2026) and the 2026-27 year, how to tell which camp you’re in, and the edge cases where people who think they don’t need to file actually do.

Need a quick sanity check? Try our IR3 filing checker — six yes/no questions to tell you whether you need to file.

The Two Systems in One Minute

Since 2019, IRD has operated two parallel end-of-year processes for individual income tax:

Automatic income tax assessment — For income IRD already knows about. Starting in late May each year, IRD runs its data against PAYE summaries, bank RWT statements, imputation credits on NZ dividends, and a few other prefilled streams. If your income is fully captured, IRD issues a notice of assessment that’s the end of your tax year. You get a refund, owe a bill, or have a zero balance. No myIR action required.

IR3 individual income tax return — The return you file yourself (or via your tax agent) in myIR. Required whenever you have income IRD can’t see automatically. You’re responsible for declaring the missing amounts, the deadline is 7 July (or 31 March of the following year if you have a tax agent with Extension of Time), and late filing attracts a fixed $50 late-filing penalty plus potential interest on any tax owed.

Critically, these aren’t alternatives you choose between. If any of your income falls outside the auto-assessment net, you must file an IR3. Auto-assessment is only “enough” when every dollar you earned is already in IRD’s system.

Auto-Assessment Covers This

IRD’s automatic assessment captures:

• Salary and wages taxed via PAYE (employer files monthly PAYE schedule)
• NZ interest where the bank withheld Resident Withholding Tax (RWT) at your notified rate
• NZ dividends with imputation credits attached (your broker / share registry reports these)
• Student allowance, NZ Super, JobSeeker and most other main benefits (MSD reports to IRD)
• Schedular payments at standard 20% withholding rates (the payer reports via IR348)
• Paid parental leave (MSD reports)

If your income is entirely these streams, you’ll get an auto-assessment and you don’t need to file an IR3.

You Must File an IR3 If You Had Any of These

These income types fall outside IRD’s pre-fill net. If you had any of them in 2025-26 — even a small amount — you must file an IR3.

Income type	Why auto-assessment can’t handle it
Self-employment / sole trader profit	Business expenses aren’t in any pre-filled data; IRD has no way to calculate net profit.
Rental property income	Letting agents’ reports go to you, not IRD. Expenses, interest deductibility, and depreciation require your disclosure.
Overseas income (salary, interest, dividends, pensions, rental)	Australian ATO, US IRS, UK HMRC don’t feed IRD individual data in real time.
Bright-line property sale	LINZ reports the sale but the profit calculation (cost base, exempt days, etc.) is yours to declare.
Shareholder-employee salary from your own company	Set at year-end; not covered by PAYE during the year.
Estate or trust distributions	Not in PAYE/RWT system; the trustee / executor reports to IRD separately.
Schedular payments at non-standard withholding rates	If you elected a different rate, the reconciliation happens on IR3.
Crypto / digital asset disposals	Exchanges don’t withhold; profit is a self-calculated amount.
Foreign Investment Fund (FIF) income over the $50,000 cost threshold	Outside PAYE / RWT systems; FDR / CV method calcs required.
Working for Families (WfF) with self-employed income	WfF square-up must include business income, which the auto process doesn’t see.

If more than one applies, you still only file one IR3 — it has supplementary forms (IR3B for business, IR3R for rental, IR3NR for non-residents) that plug in under the main return.

Worked Example 1 — Pure PAYE Earner (Auto-Assessment Wins)

Priya works a single job in Auckland. 2025-26 gross $82,000, PAYE deducted at M code. Her ASB savings account paid $340 interest, RWT withheld at 30%. She owns a handful of Spark NZ shares that paid $120 in fully-imputed dividends. That’s it.

• Salary + PAYE ✓ captured by employer
• Bank interest + RWT ✓ captured by ASB’s IR15
• NZ dividend + imputation credit ✓ captured by Link Market Services

Priya gets an automatic assessment in mid-June 2026. Small refund of $180 because her interest was slightly over-withheld at 30% vs her actual 17.5% marginal rate (the IETC also kicks in — see IETC calculator). No IR3 required.

Worked Example 2 — Side Gig + Shares (IR3 Required)

Rohan has the same $82,000 PAYE job but also runs a small weekend photography gig and earned $6,500 in cash jobs, with $1,200 of gear and travel expenses. He also holds shares in a US ETF worth $38,000 (cost basis $32,000).

• Salary + PAYE ✓ captured
• NZ bank interest + RWT ✓ captured
• Self-employment net profit $5,300 — IRD has no visibility
• US ETF FIF income — outside RWT; FIF rules apply if cost basis crosses $50k (under $50k → treat as direct share and report dividends/gains)

Rohan must file an IR3 for 2025-26 by 7 July 2026. On the return he adds the $5,300 of business income (with IR3B schedule), declares the US ETF dividend amounts gross, and claims the RWT credit.

Skipping the IR3 and letting IRD’s auto-assessment stand would under-report $5,300+ of taxable income — a shortfall that IRD data-matching (with USD-denominated ETF custodians reporting under CRS) will catch months later.

The Edge Cases That Trip People Up

“I only had schedular payments — do I need to file?” If you were withheld at the standard rate for your industry (e.g., cleaner at 20%, director’s fee at 33%), you might be auto-assessed. But most contractors elect a lower rate via IR330C, which triggers year-end reconciliation — that means an IR3.

“My overseas interest is only $80 — skip it?” No. NZ tax residents declare worldwide income. There’s no de minimis threshold for overseas income disclosure.

“I sold a rental in March for a loss — no profit, no tax, no IR3?” You still file an IR3 to disclose the bright-line or non-bright-line sale, and the ring-fenced loss carries forward. IRD expects the disclosure even when tax owing is zero.

“I’m on WfF and only get PAYE income — auto-assessment, right?” Usually yes. But if your spouse had self-employment or rental income, the WfF family square-up pulls in their IR3 numbers, which can trigger a WfF over-payment claw-back you’ll see at tax time. See our WfF square-up guide.

“I file IR3 every year — can I switch to auto-assessment if my self-employment stopped?” Yes. If your 2025-26 income is pure PAYE + NZ interest + NZ dividends, tell IRD in myIR that your tax return type changes, and they’ll auto-assess next year.

What Happens If You Don’t File an IR3 That You Should Have?

Late-filing penalty: $50 once the IR3 is over a day late, regardless of the tax outcome. Not a catastrophic number but annoying.

Use of Money Interest (UOMI): charged daily on any tax you owe from the original due date — currently 10.04% p.a. for underpayments (Q2 2026). Compounds quickly if you’re a year behind.

Reassessment by IRD: if IRD later discovers the income (via CRS data-matching, LINZ, bank reports, or audit), they’ll issue a default assessment and add shortfall penalties — 20% for a “lack of reasonable care” up to 150% for evasion. The path back is painful.

Best practice: if you think you might need to file, use our IR3 filing checker first. If you genuinely don’t need one, keep that 6-question screen as evidence.

The 2025-26 Filing Timeline

Date	Event	Applies to
31 Mar 2026	2025-26 tax year ends	All
Late May 2026	IRD auto-assessments begin issuing	PAYE / RWT / NZ dividend only
7 Jul 2026	IR3 deadline — self-filers	Anyone filing without a tax agent
31 Mar 2027	IR3 deadline — with registered tax agent	Agent EOT clients
7 Feb 2027	Terminal tax due (self-filers with RIT)	Self-employed / provisional-tax users
7 Apr 2027	Terminal tax due (tax agent EOT clients)	Agent clients

If you realise mid-year you need to file and haven’t registered a tax agent, register one before 30 June — the agent Extension of Time moves your deadline from 7 July to the following 31 March.

Sources

• IRD — Individual income tax return IR3
• IRD — Automatic calculations of income tax
• IRD — When you need to file an IR3
• IRD — Extension of time arrangements
• IRD — Use of money interest (UOMI)

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Run the 6-question IR3 filing checker before 7 July 2026

If you’re not sure which side of the line you sit on, the IR3 filing checker walks you through it in under two minutes. Already know you need to file? Use our IR3 pre-filing checklist to get everything organised, then the tax refund estimator to preview your wash-up number before opening myIR.