NZ Provisional Tax Estimation Option: When to Use It
17 October 2026 · Guide · Not tax advice
Educational information only. Not tax, legal or financial advice. We are not Inland Revenue (IRD) or ACC and are not affiliated with them. Check ird.govt.nz or ask a qualified tax agent. Sources read October 17, 2026. Anything marked expected should be re-checked. Examples use made-up numbers. This page contains no affiliate links.
Short answer: The IRD says the estimation option lets you estimate what your residual income tax (RIT) will be and pay that instead of the standard figure. It can help you avoid overpaying or underpaying if your income will change a lot. If you estimate too low you can be charged interest, and possibly a penalty. For a standard 31 March balance date, the IRD's instalment dates are 28 August, 15 January and 7 May.
When the IRD says it may suit you
- Your income will significantly increase or decrease over the next year.
- You have a loss that can be offset against your income.
- You have moved from self-employment to salary or wages where tax is already deducted.
How it works (IRD)
- You can estimate at any instalment date, or any other date up to the final instalment date.
- If you do not think you will have any RIT to pay, you can estimate at $0.
- If you estimate RIT above $60,000, provisional tax is generally paid in 3 instalments.
- If you did not have to pay provisional tax last year but choose to be a provisional taxpayer, you can use the estimation option.
The risk
You will be charged interest if your estimate is less than your actual RIT once you have filed your return. You could also be charged a penalty if your estimate is too low compared with your actual RIT. The IRD page does not give penalty rates. Re-estimate if profits move.
Made-up illustration
Your RIT last year was $20,000, so the standard option would ask for about $21,000 (RIT plus 5%). This year you expect a big drop and estimate RIT of $8,000. If your final RIT turns out to be $15,000, you underpaid by $7,000 and interest can apply on the shortfall.
Related
Standard option, dates and examples · AIM method · Use of money interest · Tax calendar
FAQ
Is 15 January the third instalment? On the standard and estimation options, IRD's table lists 28 August, 15 January and 7 May, so 15 January is the second of three.
Can I estimate after the last instalment? The page says up to the final instalment date.
What we could not verify
- Penalty rates for under-estimating (not on the page read; IR289 guide not read in full).
- Current use-of-money-interest rates.
- Instalment dates for non-March balance dates.
Sources (official)
- Inland Revenue (IRD), Estimation option — official page (read in full 17 October 2026; no review date shown)
- Inland Revenue (IRD), Payment dates for provisional tax — official page (search excerpt only, 17 October 2026)
- Inland Revenue (IRD), Provisional tax — official page (read in full 17 October 2026; no review date shown)