How this calculator helps

Dealing with GST is part of daily life for anyone running a business in New Zealand or Australia.

This calculator gives you the right number in seconds. Type in any amount, choose New Zealand (15%) or Australia (10%), and select whether to add GST or remove it from a price that already includes it. You will see a clear breakdown showing the original amount, the GST portion, and the final total. It is free, works on any device, and there is nothing to install or sign up for.

Underneath the tool you will find plain-English explanations of how GST works in both countries, the exact formulas with worked examples, the registration thresholds, filing basics, and answers to common questions. All rates and thresholds have been checked against Inland Revenue New Zealand and the Australian Taxation Office, most recently in October 2026.

How to use the calculator

1. Enter your amount. Type any dollar figure into the box. Whole dollars are fine, and so are cents.
2. Pick your country. Choose New Zealand and the calculator uses 15%. Choose Australia and it uses 10%.
3. Choose add or remove. Pick “add GST” when your price excludes GST and you want the total your customer pays. Pick “remove GST” when you have a GST-inclusive price and want to know the base amount underneath.
4. Check the breakdown. The result shows the starting amount, the GST component, and the final total separately, so there is never any doubt about which figure is which.

GST in New Zealand: the essentials

New Zealand’s GST is a flat 15% charged on most goods and services. It has been 15% since 1 October 2010. You pay it on groceries, petrol, power, phone bills, restaurant meals, clothing, and almost every service you buy.

You must register for GST with Inland Revenue when your turnover goes above $60,000 in any 12-month period. Many businesses register voluntarily below that line so they can claim GST back on what they spend. Once you are registered, you charge GST on your sales, claim it back on your business purchases, and pay Inland Revenue the difference.

Returns are filed monthly, two-monthly, or six-monthly depending on your turnover. Payment is due on the 28th of the month after your taxable period ends, although the date can shift when it lands on a weekend or public holiday.

Not everything is treated the same. Exports are zero-rated, meaning GST applies at 0% while you can still claim GST on your costs. Financial services and residential rents are exempt, meaning no GST is charged but you generally cannot claim GST on related expenses.

GST in Australia: the essentials

Australia’s GST is a flat 10% on most goods and services, unchanged since it began on 1 July 2000. It covers things like electronics, clothing, furniture, restaurant meals, and professional services.

You must register with the Australian Taxation Office once your business turnover hits $75,000 a year, or $150,000 for non-profit organisations. Taxi and limousine drivers register no matter what they earn. Like New Zealand, you can choose to register below the threshold.

GST is reported and paid through your Business Activity Statement, usually each quarter. The standard quarterly due dates are 28 October, 28 February, 28 April, and 28 July, and lodging through a tax agent can give you extra time.

Two categories deserve attention. GST-free items such as basic food, healthcare, and education are charged at 0% and you can still claim GST credits on your costs. Input-taxed items such as financial services and residential rent carry no GST, and you generally cannot claim credits on the costs behind them.

GST formulas with worked examples

You only need two formulas per country, and they are worth knowing for quick mental checks.

New Zealand (15%)

• To add GST, multiply by 1.15. A $200 job before GST becomes $200 x 1.15 = $230, so the GST portion is $30.
• To remove GST, divide by 1.15. A $230 invoice that includes GST becomes $230 / 1.15 = $200 before GST.
• Shortcut: the GST hidden inside any GST-inclusive NZ price equals the total multiplied by 3/23. For a $230 total, $230 x 3/23 = $30.

Australia (10%)

• To add GST, multiply by 1.10. A $200 job before GST becomes $200 x 1.10 = $220, so the GST portion is $20.
• To remove GST, divide by 1.10. A $220 price that includes GST becomes $220 / 1.10 = $200 before GST.
• Shortcut: the GST hidden inside any GST-inclusive Australian price equals the total divided by 11. For a $220 total, $220 / 11 = $20.

The most common slip is mixing the two rates when you deal across the Tasman, or adding 15% to a price that already includes it. If a number looks off, run it through the calculator above rather than trusting mental maths on a big invoice.

Common GST mistakes to avoid

• Treating a GST-inclusive price as GST-exclusive. Always check which one your supplier or customer means before you invoice or pay. One wrong assumption on a large job can cost you hundreds of dollars.
• Claiming GST on the wrong purchases. You cannot claim GST on exempt supplies in New Zealand or input-taxed supplies in Australia, such as bank fees and residential rent. Claims like these are a common trigger for reviews.
• Missing your filing deadline. Both Inland Revenue and the ATO charge late penalties and interest, and the interest compounds. Put the due dates in your calendar the day you register.
• Using the wrong country’s rate. If you sell into both New Zealand and Australia, double-check which rate applies to each invoice. The 15% versus 10% difference is easy to get wrong when you are busy.
• Poor records. Keep valid tax invoices for your business purchases. Without them, your GST claims can be disallowed even when the expense was genuine.

Who uses this calculator

• Freelancers and contractors working out the GST to add to an invoice.
• Tradies pricing jobs so quotes come out right the first time.
• Shop and cafe owners checking shelf prices and till totals.
• Shoppers who want to confirm the GST figure printed on a receipt.
• Bookkeepers doing fast checks before preparing a GST return or BAS.
• Businesses operating on both sides of the Tasman switching between 15% and 10%.

Popular GST tools and guides

• NZ GST calculator
• AU GST calculator
• NZ GST registration guide
• Australian GST registration guide
• BAS due dates 2026-27
• NZ GST return due dates

Frequently asked questions

What is the GST rate in New Zealand?

15%. It applies to most goods and services and has been 15% since 1 October 2010.

What is the GST rate in Australia?

10%. It has applied to most goods and services since GST was introduced on 1 July 2000.

How do I take GST out of a price?

Divide the GST-inclusive price by 1.15 in New Zealand or 1.10 in Australia. What is left is the price before GST, and the difference is the GST amount.

When do I have to register for GST?

In New Zealand, registration becomes compulsory once your turnover passes $60,000 in any 12-month period. In Australia, the threshold is $75,000 annual turnover for businesses and $150,000 for non-profits. You can register voluntarily below these levels in both countries.

What is the difference between zero-rated and exempt supplies?

In New Zealand, zero-rated supplies (like exports) are taxed at 0% and you can still claim GST on your costs, while exempt supplies (like financial services) carry no GST and generally block your claims. Australia mirrors this with GST-free versus input-taxed supplies.

Is this calculator accurate?

It applies the current official rates, 15% for New Zealand and 10% for Australia, and the guidance on this page is checked against Inland Revenue and the Australian Taxation Office. For unusual or high-stakes tax questions, speak to a qualified accountant.

Why use ANZ GST Calculator

This site is independent and unofficial, with no connection to Inland Revenue, the ATO, or any government agency. The calculators are free with no usage limits, and the guides are written for business owners rather than tax specialists. Rates, thresholds, and dates are reviewed against official sources, most recently in October 2026.