Definition
GST, or Goods and Services Tax, is a broad-based consumption tax on most goods and services. It is administered separately by Australia, New Zealand, Canada, and Singapore, each with its own rate, threshold, and return regime. The mechanic is the same: registered businesses charge GST on their sales, claim back GST on their business purchases as input tax credits, and pay or refund the net difference on a periodic return.
What GST means in practice
GST is the dominant indirect tax for any client based in AU, NZ, CA, or SG. Once a business is registered, every sale becomes a GST-inclusive transaction by default, and every business purchase becomes a candidate for an input tax credit. The bookkeeping workload is the same shape as VAT in the UK: record the gross transaction, identify the GST portion, post the net amount to the right account, and reconcile the GST control account at period end.
The complications are jurisdiction-specific. Australia has a single 10% rate but the BAS reporting cadence is quarterly for most small businesses and the cash-vs-accruals choice has real implications. New Zealand has a single 15% rate (the highest in the OECD for a no-reduced-rate regime) but filing is 2-monthly for typical SMEs. Canada has the most complex regime: 5% federal GST stacks with provincial taxes in different ways across the provinces and territories. Singapore has the lowest rate of the four (9% since January 2024) but the most aggressive electronic-invoicing mandate.
A practical example: an AU consultancy invoices AUD 11,000 GST-inclusive on a project. They have GST of AUD 1,000 on the sale. The same quarter, they buy AUD 1,650 GST-inclusive of software, which has AUD 150 of input tax credit. The net GST due on the quarterly BAS is AUD 1,000 minus AUD 150, which is AUD 850.
How GST works by country
Australia
GST is a flat 10% rate. Compulsory registration kicks in at AUD 75,000 of annual turnover for most businesses, or AUD 150,000 for non-profits. Reporting is on the BAS (Business Activity Statement), usually quarterly for SMEs and monthly above AUD 20 million. Businesses below AUD 10 million can opt for the cash GST basis. Tax invoices must include the word “Tax Invoice” prominently and the supplier’s ABN. For sales below AUD 82.50 a regular receipt is sufficient.
New Zealand
GST is a flat 15% rate (no reduced rate, the highest single-rate regime in the OECD). Compulsory registration is NZD 60,000 of taxable supplies in any 12-month period. Filing frequency defaults to 2-monthly, with monthly mandatory above NZD 24 million and 6-monthly available below NZD 500,000. The April 2023 reforms renamed “tax invoice” to “taxable supply information” but the old invoices still comply. The wording “Tax Invoice” is no longer required on the document.
Canada
Canada has the most complex GST regime. Federal GST is 5%. In Ontario, NB, NS, NL, and PEI it combines with the provincial tax to form HST at 13-15%. In AB, NT, NU, YT only the 5% federal GST applies. In BC, SK, MB, QC the 5% GST stacks with a separate PST or QST, which has its own return and recovery rules. Registration kicks in at CAD 30,000 of revenue in any single quarter or across four consecutive quarters. The CRA “no receipt no deduction” rule is strictly enforced on audit.
Singapore
GST is 9% (rose from 8% on 1 January 2024). Compulsory registration at SGD 1 million of taxable turnover. IRAS publishes detailed e-Tax Guides on the regime. The major recent change is GST InvoiceNow: from November 2025 every newly-registered business must transmit invoices on the Peppol network, and from April 2026 every GST-registered business must do so. Older paper or PDF invoices remain valid until then.
United Kingdom
The United Kingdom does not have GST. The equivalent indirect tax is VAT, at a 20% standard rate, administered by HMRC with mandatory Making Tax Digital filing.
Related terms
GST sits at the centre of indirect-tax bookkeeping in four of our five target jurisdictions:
- VAT is the UK equivalent.
- HST is the Canadian harmonised federal-plus-provincial variant.
- BAS is the Australian quarterly return that carries the GST liability.
- A tax invoice is the document required to support input tax recovery.
- An input tax credit is the amount of GST you reclaim on a business purchase.
- The GST/HST credit is a separate quarterly Canadian rebate paid to low-income individuals.
See also
For the full Australian regime see the AU GST and BAS guide. For New Zealand see the NZ GST guide. For Canada see the CA GST and HST guide. For Singapore see the SG GST guide.
FAQ
See the answered questions above for registration thresholds, the GST vs VAT distinction, and receipt documentation rules.