Tax is the most predictable bill a business has, and yet it’s one of the most common reasons owners ring the Hotline in a hurry. The problem is rarely that the tax is unfair. It’s that the cash to pay it was spent months earlier, on things that felt more urgent at the time.
This guide lays out the GST and provisional tax calendar and a few habits that make the dates much less painful. Your accountant should always have the final word on your specific obligations.
GST: the basics
GST is 15% on most goods and services sold in New Zealand. If you’re registered, you collect it from customers, claim back GST on business purchases, and pay the difference to Inland Revenue — or receive a refund if you’ve paid more than you’ve collected.
The important mindset: GST you collect isn’t your money. It’s Inland Revenue’s money, sitting in your account until the due date.
How often do you file?
Inland Revenue offers three GST filing frequencies:
| Frequency | Who it’s for |
|---|---|
| Monthly | Required for businesses with very large turnover; optional for others |
| Two-monthly | The default for most businesses |
| Six-monthly | Available to smaller businesses below IRD’s turnover threshold |
Filing more often means smaller, more frequent payments. Filing less often means larger bills. Check your current frequency in myIR, and ask your accountant whether a change would suit your cash cycle.
When is GST due?
According to Inland Revenue, your GST return is due by the 28th of the month after the end of your taxable period. Two exceptions:
- Periods ending 31 March are due 7 May.
- Periods ending 30 November are due 15 January.
Returns must be filed for every period, even if nil, and IRD doesn’t grant extensions for GST.
Provisional tax: the basics
Provisional tax isn’t a separate tax. It’s income tax paid in instalments during the year, instead of one big bill after year-end. You generally have to pay it if your residual income tax — your income tax bill after tax credits — was more than $5,000 in the previous year.
The four options
- Standard option. Based on last year’s residual income tax plus an uplift. Simple, but can bite if profits drop.
- Estimation option. You estimate this year’s income. Useful when profits fall, but you must estimate fairly and revise if things change.
- Ratio option. Linked to your GST turnover, paid alongside two-monthly GST. Spreads tax more evenly with trading.
- Accounting income method (AIM). Uses accounting software to calculate tax based on actual results as you go.
When are the instalments due?
For a standard 31 March balance date, Inland Revenue lists:
| Option | Instalments | Due dates |
|---|---|---|
| Standard or estimation | 3 | 28 August, 15 January, 7 May |
| Ratio | 6 | 28 June, 28 August, 28 October, 15 January, 28 February, 7 May |
| AIM | Usually matches GST filing | Monthly or two-monthly |
Non-standard balance dates shift these. Check the income tax account in myIR for your exact dates.
Terminal tax
After the year ends, your tax return works out the actual tax. If provisional tax paid was less than the real bill, the balance — terminal tax — is usually due in the following year. If you have a tax agent, the date may be later. Your accountant will confirm.
Why tax causes cash crunches
Look at the calendar above and you’ll see collisions:
- January. GST for November periods and the second provisional tax instalment both land on 15 January — straight after Christmas, when many businesses are shut or quiet.
- May. GST for March periods and the third provisional tax instalment both fall on 7 May, sometimes with terminal tax around the same time.
- Late August. Provisional tax on 28 August, often alongside GST.
Add PAYE — due by the 20th for most small and medium employers — and some weeks carry three tax payments.
Habits that fix it
1. A separate tax account. Open a savings account called “IRD”. Every time you’re paid, transfer the GST portion straight into it. Many owners also sweep a fixed share of each receipt to cover income tax.
2. A tax calendar. Put every GST, provisional tax and PAYE date for the next 12 months into your calendar with a reminder a week ahead.
3. Match the method to your cash. The ratio option or AIM spreads provisional tax in line with trading, which can suit seasonal businesses much better than three large instalments.
4. Tax pooling for flexibility. Tax pooling through a registered intermediary can give you flexibility on when you fund provisional tax. Ask your accountant.
5. Forecast it. Include every tax date in your cash flow forecast.
What if it’s too late for habits?
If a big GST or provisional tax bill is due and the cash isn’t there:
- Contact Inland Revenue early. You can request an instalment arrangement in myIR. Interest on overdue amounts is included in instalments.
- Keep filing. Unfiled returns make everything harder.
- Consider funding. A business loan can pay the tax in full, and a property-secured loan can refinance or pay out existing IRD debt. Our guide on IRD instalment arrangements vs a business loan compares the options.
Talk it through
If a tax date is looming, ring the Hotline. A specialist will help you weigh up an IRD arrangement against funding, honestly. Or request a call back.
Ready when you are. Ring 09 875 4577 or request a call back — a lending specialist will talk it through.