Filing Your GST Return in NZ: A Step-by-Step Walkthrough

_Disclaimer: The information provided in this article is for general guidance only and does not constitute professional financial advice. Your financial situation is unique, and we recommend seeking personalised advice from a qualified professional before making any decisions._

• Filing a GST return involves calculating the GST you've collected on sales minus the GST you've paid on business expenses.
• The standard due date for filing your GST return and making any payment is the 28th of the month after your taxable period ends.
• Most GST returns are filed online through the Inland Revenue's myIR portal, which automatically calculates your position.
• You must register for GST if your business turnover exceeds or is expected to exceed $60,000 in any 12-month period.
• Keeping accurate records of all sales and purchases is the most critical step for a stress-free GST filing process.

For many business owners here in Hawke's Bay, the words "GST return" can trigger a mild headache. It often feels like another chore on an already overflowing to-do list. But it doesn't have to be that way. We're here to show you that filing your Goods and Services Tax (GST) return is a manageable, and even empowering, part of running a successful business.

And it's a significant part of the NZ economy. To give you some perspective on its scale, since June 2001, net GST revenue in New Zealand has surged by an incredible 326%, climbing from $9.9 billion to an estimated $42.1 billion by June 2025. This single tax makes up a huge portion of the government's funds, with total tax revenue reaching $129.4 billion for the year ending June 2025.

You’re not alone in this. For the year ended March 2025, there were 671,324 taxpayers registered for GST and actively submitting returns in New Zealand. Every one of those returns, including yours, plays a part. Let's break down how to file your GST correctly, efficiently, and with confidence.

At its heart, GST is a 15% tax added to the price of most goods and services in New Zealand. If you're a GST-registered business, you act as a collection agent for the Inland Revenue (IRD). You charge GST on your sales and income, and you can claim back the GST you’ve paid on business expenses. The difference is what you either pay to the IRD or what they refund to you.

The key trigger for registration is your turnover. If your annual turnover exceeds, or is likely to exceed, $60,000 in a 12-month period, you must register for GST. For a complete breakdown of the rules, we recommend understanding the basics of Goods & Services Tax before you begin.

Before you can file, you need to know your filing frequency, also known as your taxable period. This is determined when you first complete your GST registration. There are three options:

• Two-monthly: This is the most common option for small businesses. Your taxable period ends every second month (e.g., February/March, April/May).
• Monthly: This is mandatory for businesses with a turnover of $24 million or more. However, smaller businesses can also opt for it. In our experience, this is a great choice if you consistently receive a GST refund, as you get that cash back into your business faster.
• Six-monthly: If your turnover is less than $500,000 a year, you can choose to file every six months. This means less frequent admin, but it also requires discipline to set aside the GST collected over a longer period.

Choosing the right frequency depends on your cash flow and admin capacity. You can change your filing frequency later on, but it's good to start with one that suits your business needs.

Alright, let's get into the practical steps. Once your taxable period ends, it's time to prepare and file your return. Here’s how we walk our clients through it.

Step 1: Gather Your Records

This is the most important step. Good records make filing a breeze; poor records make it a nightmare. For the taxable period you're filing for, you need a clear record of two things: your sales and your purchases.

This means having all your sales invoices, cash sale records, and details of any other income. It also means having every receipt and tax invoice for your business expenses. Think office supplies, fuel, software subscriptions, professional fees, and materials.

Step 2: Calculate Your Figures

Now you need to add it all up. You'll calculate:

1. Total Sales and Income: The total amount of money your business has earned during the period (including GST).
2. Total Purchases and Expenses: The total amount you've spent on business-related goods and services (including GST).

How you calculate this depends on your accounting basis. There are three methods: the Payments Basis (based on actual money received and paid), the Invoice Basis (based on invoice dates, regardless of when they're paid), and the Hybrid Basis. For most sole traders and small businesses, the Payments Basis is the simplest to manage as it directly reflects what's in your bank account.

Once you have these two totals, the basic formula is simple: calculate the GST on your sales, then subtract the GST on your expenses. The result is either the GST you owe or the refund you're due.

Step 3: Filing Your Return Through myIR

These days, almost everyone files their GST return online via the IRD's `myIR` service. It's fast, secure, and it does the hard maths for you.

Here’s the process:

• Log in to your `myIR` account.
• Navigate to your GST account.
• Select the return for the correct taxable period.
• You'll see boxes for "Total sales and income" and "Total purchases and expenses".
• Enter the figures you calculated in Step 2. `myIR` will calculate the GST portion automatically.
• As you enter the numbers, the system will show you whether you owe GST or are due a GST refund.
• Carefully review all the information before you click "Submit". Once submitted, it's a legal declaration.

Over the years, we've seen a few common trip-ups. Here are the main ones to watch out for:

• Forgetting to Claim All Your GST: It's easy to miss small expenses, but they add up! A common mistake we observe is business owners forgetting to claim the GST on things like their phone bill, internet, or that software subscription that auto-renews. Keep every single business receipt.
• Mixing Business and Private Use: If you buy an asset, like a car or a laptop, that you use for both business and personal reasons, you can only claim the GST for the business-use portion. You need to make a reasonable adjustment for any private use.
• Missing the Due Date: Your GST return is generally due by the 28th of the month following the end of your taxable period. For example, the return for the January/February period is due by 28th March. Missing the due date can result in late filing penalties and interest, so mark it in your calendar!

How do I get my GST refund back?

If your return shows you've paid more GST on expenses than you've collected on sales, the IRD owes you a refund. This is great for your cash flow! After you file a GST return showing a refund is due, the IRD will process it and typically deposit the money directly into your nominated New Zealand bank account within 15 working days.

What if I owe GST?

If you collected more GST than you paid, you need to pay the difference to the IRD. The payment is due on the same day as your return, the 28th of the month. You can pay easily through your `myIR` account, via direct debit, or online banking.

Managing your GST is a fundamental part of good business practice in New Zealand. It's a rhythm you get into. By keeping clean records and understanding the process, you can turn it from a source of stress into a simple, routine task.

And if it ever feels like too much, that's what we're here for. Getting expert help can save you time, money, and a lot of worry. For more expert advice on a range of tax topics, explore our comprehensive Tax Facts , or get in touch with our Hawke's Bay team today.