NZ Company Provisional Tax: Which Calculation Method to Choose in 2026

Provisional Tax: The Year-One Trap for New NZ Companies

Most new NZ company directors are surprised by provisional tax. Unlike PAYE (which is withheld before you see your salary), provisional tax requires you to pre-pay income tax in instalments during the year -- before your tax return is filed. Get it wrong and you face use-of-money interest (currently 10.39% p.a.) on any underpayment.

For a company that earns its first real revenue in year one, this can mean a significant unexpected cash outflow in year two.

The Three Calculation Methods

1. Standard Uplift Method

The default for most companies. Provisional tax = 105% of the prior year's residual income tax (RIT). For new companies with no prior year, this means no provisional tax in year one -- but year two can be a shock if year one was profitable.

Best for: Stable, predictable income businesses. Simple to manage.

Risk: If your income grows significantly year-on-year, 105% of last year may leave you underpaying.

2. Estimation Method

You estimate your own income for the current year and calculate provisional tax based on that estimate. You can revise the estimate right up to the third instalment date.

Best for: Companies with variable income, first-year profitability uncertainty, or known large transactions.

Risk: Underestimate and you pay use-of-money interest. Overestimate and you've overpaid (refund on tax return, but cash flow cost).

3. Ratio Method

Pay provisional tax as a percentage of each GST return (available only if you file GST 2-monthly). The ratio is calculated by IRD based on your prior year data.

Best for: Businesses where income closely tracks GST taxable supplies -- retail, hospitality, trades.

Not available for: First-year companies (no prior data); companies with significant non-GST income.

2026 Provisional Tax Instalment Dates

For a standard 31 March balance date:

• 1st instalment: 28 August 2025
• 2nd instalment: 15 January 2026
• 3rd instalment: 7 May 2026

If your company has a non-standard balance date, instalment dates shift accordingly. Ask your accountant for the specific dates for your situation.

What New Companies Should Do

1. Set up a tax reserve account from day one -- deposit 28 cents per dollar of net profit each month.
2. Engage an accountant before your first GST return -- they will confirm your year-one provisional tax exposure and help you choose the right method.
3. Do not wait for IRD to contact you -- provisional tax obligations arise automatically once your residual income tax exceeds NZ$5,000.

For NZ Accountants: Reaching New Companies Before Their First Provisional Tax Obligation

New NZ companies typically register and begin trading without any professional tax guidance. The first provisional tax instalment arrives before most new directors have engaged an accountant. FreshFirms lets you reach newly-incorporated companies in your region in the first 30 days -- when the GST, PAYE, and provisional tax questions are all live and unanswered.

Pro subscribers get daily alerts with director contact details for new companies in their region.