GST Registration Australia: $75k Threshold and BAS Guide

Quick answer: GST registration in Australia is required within 21 days once your business's GST turnover reaches $75,000 or more ($150,000 for non-profits), or is projected to, and immediately for taxi and ride-sourcing drivers. You need an ABN first, then register through the ABR, Online services for business or a tax agent. Registered businesses charge 10% GST and lodge a BAS.

For most small businesses in Australia, GST registration is the moment the tax side of the business gets real: prices may change, invoices become tax invoices, and the business activity statement (BAS) arrives every quarter. This guide explains the $75,000 threshold, how to work out GST turnover, the registration steps, BAS lodgment dates, the cash versus accrual choice, and what your invoices need to show, with a worked example.

This is general information, not tax advice. Rules and dates are from the ATO as of October 2026; confirm them with the ATO or a registered tax or BAS agent.

What is GST in Australia?

The goods and services tax is a broad-based 10% tax on most goods, services and other items sold or consumed in Australia. Registered businesses add GST to the price of taxable sales, collect it from customers, and pay it to the ATO, while claiming back the GST included in their business purchases (GST credits). Some sales are GST-free, such as most basic food, some health and education services and many exports. Others are input-taxed, such as residential rent and most financial supplies, which means no GST is charged and no credits are claimed for related costs.

When do you need to register for GST in Australia?

According to the ATO's registering for GST page, you must register if you are carrying on an enterprise and any of the following apply:

• your GST turnover is $75,000 or more (current or projected);
• you are a non-profit organisation with GST turnover of $150,000 or more;
• you provide taxi or limousine travel, including ride-sourcing, regardless of turnover;
• you want to claim fuel tax credits.

You must register within 21 days of becoming required to. Non-resident businesses selling to Australian consumers have their own simplified registration rules.

How to work out GST turnover

GST turnover is your gross business income, excluding GST, input-taxed sales, sales not connected with your business and sales not made for payment. You reach the threshold under either test:

Test	Period	You must register if
Current GST turnover	This month plus the previous 11 months	The total is $75,000 or more
Projected GST turnover	This month plus the next 11 months	The total is likely to be $75,000 or more

The projected test catches fast-growing businesses early. If you sign a $90,000 contract in your first month, your projected turnover is already over the threshold, so you need to register within 21 days, even though you have not earned $75,000 yet.

Worked example of the turnover test

Raj started a consulting business in July 2025. His monthly sales (excluding GST) averaged $5,500 until March 2026, then rose to $8,000 from April. At the end of June 2026, his 12-month total is 9 x $5,500 plus 3 x $8,000, or $73,500, still under $75,000. But in June he can reasonably project $8,000 a month for the next 12 months, or $96,000. Under the projected turnover test he has reached the threshold and must register within 21 days.

How to register for GST in Australia: step by step

1. Get an ABN. You cannot register for GST without one. If you do not have one, our guide on how to get an ABN covers the free application, and you can register for GST in the same form.
2. Choose how to register. Use Online services for business, the Australian Business Register website, a registered tax or BAS agent, or phone the ATO.
3. Pick your effective date. For required registration, it is the date you reached the threshold. Voluntary registrants can usually choose a date.
4. Choose your accounting method. Cash or accrual (non-cash). Most small businesses with aggregated turnover under $10 million can use cash.
5. Choose your reporting cycle. Quarterly is the default for small businesses. Monthly is required if GST turnover is $20 million or more and can be chosen voluntarily. Annual is available to voluntary registrants under $75,000.
6. Update prices and invoices. Decide whether to absorb GST or add it on, and change invoices to tax invoices from your effective date.

What is a BAS and when is it due?

The business activity statement (BAS) is the form you use to report and pay GST, plus other taxes such as PAYG instalments and PAYG withholding for employees. For GST you report total sales (G1), GST on sales (1A) and GST on purchases (1B), and pay or receive the difference.

Quarter	Period	Standard due date
Quarter 1	July to September	28 October
Quarter 2	October to December	28 February
Quarter 3	January to March	28 April
Quarter 4	April to June	28 July

Monthly BAS is generally due on the 21st of the following month. Lodging through a registered tax or BAS agent can give you extra time on quarterly due dates. When a due date falls on a weekend or public holiday, you can lodge and pay on the next business day. Late lodgment can attract a failure to lodge penalty, and unpaid amounts accrue the general interest charge.

Worked BAS example

Raj's first full quarter after registering is July to September 2026. He invoices $26,400 including GST and buys a laptop and software for $3,300 including GST.

BAS item	Calculation	Amount
G1 Total sales (incl. GST)	From invoices	$26,400
1A GST on sales	$26,400 / 11	$2,400
1B GST on purchases	$3,300 / 11	$300
Net GST payable	$2,400 - $300	$2,100

Raj lodges and pays $2,100 by 28 October. Dividing a GST-inclusive amount by 11 gives the GST component. For quick checks, the sales tax calculator handles 10% GST in both directions, and our reverse tax calculation article shows the formula.

What changes on your invoices after GST registration?

Once registered, you issue tax invoices for taxable sales. A customer who asks for a tax invoice for a sale over $82.50 (including GST) must receive one within 28 days. A tax invoice generally needs to show that it is intended to be a tax invoice, your identity and ABN, the date, a brief description of items sold, the GST amount (or that the total includes GST), and for sales of $1,000 or more, the buyer's identity or ABN. Our Australian tax invoice requirements guide goes through each element.

Description	Qty	Unit price (ex GST)	Amount
Business process review workshop	1	$4,500.00	$4,500.00
Follow-up consulting (hours)	12	$180.00	$2,160.00
Written recommendations report	1	$1,340.00	$1,340.00
Subtotal			$8,000.00
GST 10%			$800.00
Total (incl. GST)			$8,800.00

The header would read "Tax invoice" with Raj's ABN, the client's business name and ABN (because the sale is over $1,000), the invoice number and the date. Set your GST rate and ABN once in the free invoice generator and every tax invoice calculates the 10% for you.

How should you price after registering for GST?

Australian consumer law requires prices advertised to consumers to include GST, so shops and consumer-facing services generally quote GST-inclusive prices. Business-to-business quotes are often written as a price plus GST, as long as the total is clear. When you register, you have three broad options for existing prices:

Option	Price before registration	Price after registration	Your income (ex GST)
Add GST on top	$1,000	$1,100 incl. GST	$1,000.00
Absorb GST	$1,000	$1,000 incl. GST	$909.09
Split the difference	$1,000	$1,050 incl. GST	$954.55

Business clients registered for GST will usually accept the first option because they claim the $100 back. Consumers bear the full increase, so many consumer businesses absorb part of it. Whatever you choose, show the subtotal, GST and total clearly so the client understands the bill; our explainer on net vs gross amounts on an invoice covers the labels to use. If you give a discount, apply it before calculating GST, as our tax invoice guide shows.

Tell existing clients about the change before your first GST invoice, ideally in writing with the effective date. For retainers and recurring work, update each recurring invoice so the GST line starts from the right billing period.

Should you register for GST voluntarily?

• Business customers can claim the GST you charge as a credit, so adding 10% rarely puts them off.
• Consumer customers cannot, so you either raise prices by 10% or absorb the GST and earn less.
• High setup costs such as equipment, vehicles or fit-outs mean bigger GST credits.
• Admin increases: BAS lodgment, tax invoices and more careful record keeping.
• Annual reporting is available for voluntary registrants under $75,000, which keeps the extra admin light.

What records do GST-registered businesses need to keep?

The ATO generally expects you to keep records that explain your GST position for five years. That includes copies of the tax invoices you issue, tax invoices from suppliers for purchases where you claim GST credits, adjustment notes for refunds and price changes, bank statements, and the working papers behind each BAS. Records can be paper or digital, but they must be in English or easily converted, and they must show how you calculated each label on the activity statement. If a customer returns goods or you give a later discount, issue an adjustment note rather than changing the original invoice; our credit note guide explains the same principle in general terms. Keeping invoices numbered in one unbroken sequence makes your BAS easy to reconcile with your bank deposits.

Common GST registration mistakes

• Ignoring projected turnover. Looking only at the past 12 months misses the forward-looking test.
• Forgetting the 21-day deadline. Late registration can be backdated, with GST owed on past sales.
• Not repricing. If your price stays the same after registration, one eleventh of every GST-inclusive sale now goes to the ATO.
• Claiming credits without tax invoices. For purchases over $82.50 including GST, you generally need a valid tax invoice before claiming.
• Charging GST on GST-free or input-taxed sales. Classify each product or service correctly.
• Spending GST collected. Keep the GST portion of each payment in a separate account until BAS time. Our cash flow management guide has practical systems.

GST registration checklist

• Check current and projected GST turnover every month.
• Get an ABN, then register for GST within 21 days of reaching $75,000.
• Choose cash or accrual accounting and a reporting cycle.
• Update prices, quotes and invoice templates to show GST and "Tax invoice".
• Diary BAS due dates and set aside GST from every payment.
• Keep tax invoices for purchases and records for five years.

For how Australia's GST compares to VAT and US sales tax, see our sales tax vs VAT vs GST comparison.

After GST registration in Australia, every invoice you send needs to be a correct tax invoice. Our invoice generator is free, needs no sign-up, and creates a downloadable PDF in your browser with your ABN, GST line and totals already worked out.