NZ Provisional Tax for New Companies: What Founders Need to Know
Provisional tax is one of the biggest surprises for new NZ business owners. This guide explains when it kicks in, how to estimate it, and how to avoid interest and penalties.
What Is Provisional Tax?
Provisional tax is a way of paying income tax in instalments during the tax year, rather than paying a large lump sum after the year ends. It is separate from GST and applies to businesses and individuals whose residual income tax (RIT) exceeds NZ$5,000 in a year.
For most new companies, provisional tax becomes relevant in the second year of trading, once the first year's income tax return is filed and the RIT for that year is known. However, if your income grows quickly in year one, you may owe residual income tax earlier than expected.
When Does Provisional Tax Apply to a New Company?
In your first full tax year, you typically pay standard income tax on what you earn. At the end of the year, you file your tax return. If your RIT is more than NZ$5,000, you become a provisional taxpayer the following year.
This means in year two, you must pay tax during the year, not just at the end. Provisional tax is usually paid in three instalments (using the standard uplift method) or across monthly payments (using the accounting income method).
Methods of Paying Provisional Tax
Standard Uplift Method
The default method. IRD calculates your provisional tax based on last year's RIT plus 5%. Payments are due in three instalments during the year (typically August, January, and May for a March balance date).
Estimation Method
You estimate your current year's income and calculate tax accordingly. Useful if you expect income to be significantly lower than last year. If you underestimate, IRD charges interest on the shortfall.
Accounting Income Method (AIM)
A newer method using accounting software to calculate provisional tax based on your actual income each period. AIM eliminates the risk of underpaying or overpaying, and is available through accounting platforms like Xero. Interest does not apply if you use AIM correctly.
Safe Harbour: Who Is Exempt?
If your previous year's RIT was NZ$60,000 or less (the safe harbour threshold as at 2026), no interest is charged if you pay the standard uplift amount on time, even if your actual tax turns out to be higher. This is a significant protection for most small businesses.
Common Mistakes New Business Owners Make
- Assuming provisional tax does not apply until year three or four
- Not setting aside money for provisional tax during the trading year
- Underestimating income growth and ending up with a large shortfall
- Missing an instalment date, which triggers interest immediately
- Not using AIM when it would save interest and improve cashflow
How to Set Yourself Up Correctly
The best way to manage provisional tax is to work with an accountant from the start. A good accountant will:
- Help you understand when you will first become a provisional taxpayer
- Set up a regular tax savings habit so you are never caught short
- Advise on whether AIM is appropriate for your business
- File your returns on time and monitor your IRD account
If you need a local accountant in your region, FreshFirms Connect can match you with an accountant who specialises in new businesses.
Key Dates (March Balance Date)
- First instalment: 28 August
- Second instalment: 15 January
- Third instalment: 7 May
- Terminal tax (any balance): 7 April the following year
Dates may vary depending on your balance date and whether you have a tax agent extension. An accountant or tax agent can confirm your specific due dates.