Provisional tax in New Zealand: A guide for small business owners
Learn how provisional tax helps you plan cash, avoid interest, and stay on top of payments across the year.
Written by Naomi Lai— Small business & finance writer. Read Naomi's full bio
Published Thursday 23 July 2026
Table of contents
Key takeaways
- Provisional tax spreads your income tax across the year once your residual income tax exceeds $5,000, helping you manage cash flow and avoid a large year-end bill.
- Choose a calculation method that matches your income pattern: standard uplift for steady growth, estimation for drops, AIM for real-time alignment, or ratio if profit tracks sales.
- You can adjust payments mid-year by updating your estimate, switching methods at allowed times, or using tax pooling to fine-tune timing and reduce interest costs.
- Check Inland Revenue Department dates to plan provisional tax payments on time and set calendar reminders to avoid interest.
What is provisional tax in New Zealand?
Provisional tax is a way to spread your income tax payments across the year rather than paying a lump sum at the end. It applies to businesses, contractors, and anyone earning income that isn't taxed at source through pay as you earn (PAYE).
If your residual income tax (RIT), the tax you owe after PAYE, credits, and prior payments, exceeds $5,000 in a tax year, you'll need to pay provisional tax the following year. This threshold helps small businesses avoid large, unexpected tax bills and keeps cash flow smoother.
The Inland Revenue Department (IRD) administers provisional tax in New Zealand. You can find full details and guidance on the IRD’s provisional tax overview page.
The system is designed to match your tax payments to your income as you earn it, so you're not hit with a big bill when you file your return. It's about paying tax in instalments throughout the year, based on either your previous year's results or your current year's forecast.
Who needs to pay provisional tax?
You'll pay provisional tax if you're a sole trader, contractor, company, or trust with untaxed income and residual income tax over $5,000. This includes several types of income:
- business profits from trading or services
- contracting income where PAYE isn't deducted
- rental property profit (after expenses)
- overseas income not taxed at source
- investment income above the threshold
If your residual income tax is $5,000 or less, you'll pay terminal tax only when you file your return. Once you cross that threshold, provisional tax kicks in for the next year.
Most small businesses reach the $5,000 RIT threshold as they grow, so it's worth planning ahead even if you're not there yet. Your accountant or bookkeeper can help you forecast whether you'll need to pay provisional tax based on your current profit trends.
When are provisional tax dates in NZ?
Provisional tax dates in NZ depend on your balance date and the calculation method you choose. Under the standard uplift or estimation methods, you'll make three instalments during the year.
If you use the accounting income method (AIM) or the ratio option, your provisional tax payments in New Zealand align with your goods and services tax (GST) filing cycle, such as one-monthly, two-monthly, or six-monthly, giving you more frequent, smaller payments that match your cash flow.
Check your personalised dates in myIR and set calendar reminders to avoid late payment interest. Missing a payment can trigger use-of-money interest charges, so staying on top of dates protects your cash position.
Example dates for a March balance date
If your balance date is 31 March, your three instalments under standard uplift or estimation typically fall on:
- 28 August (first instalment)
- 15 January (second instalment)
- 7 May (third instalment, plus any terminal tax adjustment)
These dates shift slightly depending on weekends and public holidays, so always confirm your specific dates in myIR or with your advisor.
Non-standard balance dates
Your provisional tax dates shift if your balance date isn't 31 March. Businesses with a June, September, or December balance date follow a different instalment schedule set by the IRD.
Log in to myIR to see your personalised due dates, or check the IRD provisional tax due dates page for the full schedule by balance date.
What happens if I miss a provisional tax payment?
Missing a provisional tax payment triggers automatic penalties and interest from the IRD. The charges are applied in stages, so acting quickly can reduce the total cost to your business.
If you miss a due date:
- A 1% late payment penalty is charged the day after the due date.
- A further 4% penalty is charged six days after the due date if the amount is still unpaid.
- Use-of-money interest (UOMI) accrues daily on the unpaid amount until it is settled.
If you have missed a payment, it’s best to contact the IRD as soon as possible. You may be able to set up a payment plan or use a service like tax pooling to manage the shortfall and limit the penalties.
How do you calculate provisional tax?
To calculate your provisional tax, follow these steps:
- Choose a calculation method that suits your income pattern, such as standard uplift, estimation, accounting income method (AIM), or the ratio option.
- Work out your expected residual income tax (RIT) for the year using that method.
- Divide your total provisional tax by the number of instalments for your chosen method.
- Pay each instalment by the due dates for your balance date.
The IRD offers four methods to calculate provisional tax, and your choice depends on how stable your income is and whether you file GST returns. You'll generally use one method for the full tax year unless the IRD allows a change. Each method has trade-offs between simplicity and accuracy.
Standard uplift option
Base this year's provisional tax on last year's (or the prior year's) residual income tax, plus an uplift of 5% (or 10% if you haven't filed recent returns). This suits businesses with steady or growing profit and requires minimal admin.
Example: If your RIT last year was $10,000, your provisional tax this year is $10,000 × 1.05 = $10,500, split across three instalments.
For detailed steps, see the IRD page on working out provisional tax using the standard option.
Estimation option
Estimate your current-year residual income tax and pay instalments to match that figure. This is useful if you expect profit to drop, as it reduces your payments. However, if you underestimate by more than the safe harbour threshold, you'll face use-of-money interest on the shortfall.
Example: You forecast $8,000 RIT this year (down from $10,000 last year). You can estimate $8,000 and pay $2,667 per instalment, but if your actual RIT is $9,500, you may owe interest on the difference.
Accounting income method (AIM)
Calculate and pay provisional tax during the year through approved software, based on your actual profit each period. AIM aligns payments with real-time results and removes the risk of interest for underpayment, as long as you meet eligibility rules (turnover under $5 million, up-to-date GST and tax filings).
Example: Your profit for the first two months is $3,000, so you calculate tax on $3,000 and pay it with your GST return. Next period, profit is $4,500, so you calculate and pay tax on that amount. Payments match income as it happens.
For more on AIM eligibility and how it works, see the IRD calculating provisional tax page.
Ratio option
Pay a set percentage of your GST-exclusive sales each GST period. You need GST registration and IRD approval to use this method. It works best when profit consistently tracks sales, such as in retail or hospitality.
Example: The IRD approves a ratio of 4% of sales. If your GST-exclusive sales are $50,000 this period, you pay $2,000 provisional tax.
How do you pay provisional tax to the IRD?
You have several options to make your provisional tax payments:
- Pay in myIR. Log in, select the income tax type, and choose the correct period. This is the most straightforward method and gives you instant confirmation.
- Make a bank transfer. Use Inland Revenue's bank account details, include your IRD number, the correct tax type code (for example, INC for income tax), and the period. Double-check these details so the IRD can match your payment correctly.
- Use tax pooling. Work with an approved tax pooling provider for more flexibility on timing. This can help you avoid interest if your payment is late or if you need to adjust amounts after the due date.
For detailed payment instructions and bank account details, visit the IRD provisional tax payment page.
What are your options if your income changes?
If your income rises or falls during the year, you can adjust your provisional tax to match current results and manage use-of-money interest. Staying flexible protects cash flow and ensures you're not overpaying or underpaying.
Here are practical options to stay on track:
- Update your estimate during the year to match actual performance. You can revise your estimate in myIR or notify the IRD in writing, then adjust your remaining instalments.
- Switch to AIM or the ratio option at allowed times if they fit your business better. AIM is available from the start of your tax year if you're eligible; the ratio option requires IRD approval.
- Use tax pooling to fine-tune timing and reduce interest cost. Tax pooling lets you buy or sell provisional tax after the due date, smoothing out mismatches between payments and actual tax.
- Build a monthly set-aside for expected provisional and terminal tax. Treat tax like any other regular expense and move funds into a separate account each month so the cash is ready when instalments fall due.
For guidance on making changes, visit the IRD making changes to provisional tax page.
Changing methods and impacts
You can change methods at specific points in the year, but you'll need to notify the IRD and follow their process. Switching from standard uplift to estimation, for example, requires you to file a new estimate before the next instalment is due.
If you estimate too low, you may face use-of-money interest on the shortfall. The safe harbour rules protect you from interest if your estimate is within certain thresholds, but it's safer to update your estimate as soon as you see income trending higher than expected.
If your profits are volatile or you have multiple entities, get advice from your accountant or bookkeeper. They can model different scenarios and recommend the method that minimises interest and admin for your situation.
What is different in your first year?
Most new businesses pay terminal tax in the year after they start trading, often alongside the first year of provisional tax for the following year. This can create a cash crunch if you're not prepared, as you're effectively paying two years of tax at once.
In your first year as a provisional taxpayer, the IRD generally won’t charge use-of-money interest on underpaid provisional tax. This gives you some breathing room but doesn’t mean you can ignore the payments entirely. Late payment penalties can still apply.
Plan ahead by setting aside funds monthly from day one. Forecast your profit early in the year and estimate what your terminal and first provisional tax bills will be. Many businesses underestimate this and struggle with cash flow when the bills arrive.
In your second year, consider using AIM if your income is variable. AIM spreads payments across the year based on actual results, so you're not locked into an estimate that might be too high or too low. This is especially helpful if you're still finding your feet and revenue is unpredictable.
Your accountant or bookkeeper can help you forecast tax liabilities and set up a monthly savings plan. Treat tax as a regular cost of doing business, not a surprise bill, and you'll avoid stress and keep your cash position healthy.
Simplify provisional tax planning with Xero
Managing provisional tax gets easier when your numbers are up to date and in one place. Xero gives you clear reports so you can forecast income, plan for tax, and stay on top of your cash flow.
FAQs on provisional tax
Here are short answers to common questions about provisional tax in New Zealand. Use them to clarify key points and plan how you'll manage your payments.
How much is provisional tax in NZ?
Your provisional tax is the total residual income tax (RIT) you expect to owe for the year, split across two or three instalments depending on your calculation method. The amount varies by business; see the calculation methods section above to work out your figure.
How is provisional income taxed?
Provisional income isn't taxed differently from other income. The provisional tax system simply spreads your income tax payments across the year. You calculate the total tax you expect to owe, then pay it in instalments. At year-end, any difference between what you paid and what you actually owe is settled as terminal tax (a top-up) or a refund.
Can I get a refund on provisional tax?
Yes. If you pay more provisional tax than your actual residual income tax for the year, Inland Revenue will refund the difference when you file your return. This can happen if you overestimate your income or if your profit drops after you've already made payments. The refund is usually processed within a few weeks of filing.
What is residual income tax?
Residual income tax (RIT) is the income tax you owe after PAYE, tax credits, and any other payments or deductions are taken into account. It's the final tax bill that appears when you file your return. If your RIT is over $5,000, you'll pay provisional tax the following year to spread that liability across instalments.
What are IRD provisional tax dates?
IRD provisional tax dates depend on your balance date and the method you use. Under standard uplift or estimation, you'll have three instalments during the year. For a 31 March balance date, the typical dates are 28 August, 15 January, and 7 May. If you use AIM or the ratio option, payments align with your GST cycle. Check your personalised dates in myIR or see the IRD payment dates for provisional tax page.
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