You must register for GST in Singapore when your taxable turnover for a calendar year is more than S$1 million (the retrospective basis), or when you can reasonably expect it to be more than S$1 million in the next 12 months (the prospective basis). Below that, registering is voluntary. Once registered, you charge GST at 9%, issue tax invoices, file a GST return every quarter and, in phases, send invoice data to IRAS by e-invoice.
Until you're registered, don't add GST to your prices: only GST-registered businesses may charge it, and collecting GST without being registered is an offence.
What counts as taxable turnover
Taxable turnover is the value of your standard-rated and zero-rated supplies. Leave out exempt supplies, out-of-scope supplies and the sale of capital assets such as machinery, equipment, office buildings and furniture. A caterer who sells an old combi oven for S$6,000 doesn't count it towards the S$1 million.
The retrospective basis: looking back at the year
At the end of each calendar year, check whether taxable turnover from 1 January to 31 December was more than S$1 million. If it was, apply for GST registration between 1 and 30 January of the following year, and you'll be registered from 1 March.
Example: a wholesaler's taxable turnover for 2026 is S$1.08 million. It applies by 30 January 2027 and is GST-registered from 1 March 2027.
The prospective basis: looking ahead 12 months
If at any point you can reasonably expect taxable turnover of more than S$1 million in the next 12 months, for example because you've signed a large contract, you must apply within 30 days after the date of that forecast. For forecasts made on or after 1 July 2025, you're registered two months from the forecast date, which gives you a two-month grace period before you start charging GST.
Example: a renovation contractor signs S$1.2 million of work to be done over the next year on 10 November 2026. It applies by 10 December 2026 and is registered from 10 January 2027.
If you register late
Registration is backdated to the date you should have been registered, and you pay GST on sales from that date even though you didn't collect it. Late registration can bring a fine of up to S$10,000 and a penalty of 10% of the GST due. If you tell IRAS about the lateness when you apply, the fine and penalties are generally waived, though the GST is still due.
If your taxable turnover is wholly or mainly from zero-rated supplies, such as exports, you can apply to be exempt from registration instead.
Registering voluntarily
Below S$1 million you can choose to register. IRAS lists the benefits as claiming the GST you pay on purchases (input tax), and not having to watch your turnover constantly if it's close to the threshold. The costs: more admin, possibly absorbing the GST if your customers aren't GST-registered, and not being able to claim input tax in full if you're partially exempt.
A voluntary registration lasts at least two years, so IRAS suggests weighing costs and benefits over that period. There are other conditions before and after registering, set out in IRAS's guide. And from 1 April 2026, every new voluntary registrant must send invoice data to IRAS by e-invoice (from 1 November 2025 for companies registering voluntarily within six months of incorporation). You apply online on IRAS's myTax Portal.
What changes once you're registered
Late filing costs S$200 straight away and S$200 more for every completed month the return is outstanding, up to S$10,000 a return. If you don't file, IRAS can issue an estimated assessment with a 5% late payment penalty on the estimated tax.
- Charge GST at 9% on standard-rated supplies.
- Show prices to the public inclusive of GST: price tags, price lists, advertisements, brochures, websites, and prices you quote in writing or out loud.
- Issue a tax invoice to a GST-registered customer within 30 days of the supply. For a customer who isn't GST-registered, a receipt will do.
- File a GST return (Form GST F5) for each accounting period, normally three months, and pay within one month after the period ends. File a nil return even when there were no sales.
- Claim input tax on business purchases, subject to IRAS's conditions.
- Keep records for at least five years.
Tax invoices, simplified tax invoices and receipts
IRAS's requirements for each document, in short:
| Document | When to use it | What it must show |
|---|---|---|
| Tax invoice | For a GST-registered customer, within 30 days of the supply | The words 'tax invoice'; your name, address and GST registration number; invoice number and date; the customer's name and address; a description; the GST rate; the amount before GST, the GST and the total including GST |
| Simplified tax invoice | When the total including GST is S$1,000 or less | Your name, address and GST registration number; invoice number and date; a description; the total including GST; a statement such as 'Price payable includes GST' |
| Receipt | For a customer who isn't GST-registered | A serial number; the date; your name and GST registration number; the total including GST; a statement that the price includes GST |
GST e-invoicing: what the requirement means
Singapore has a nationwide e-invoicing network, and IRAS is making it compulsory for GST-registered businesses in phases: they must submit invoice data to IRAS using an IMDA-accredited e-invoicing solution. The phases:
| From | Who |
|---|---|
| 1 November 2025 | Companies that register for GST voluntarily within 6 months of incorporation |
| 1 April 2026 | Every business applying for voluntary GST registration from this date |
| 1 April 2028 | Businesses applying for compulsory registration from this date, and existing GST-registered businesses with total annual supplies of S$200,000 or less |
| 1 April 2029 | Existing GST-registered businesses with total annual supplies of S$1,000,000 or less |
| 1 April 2030 | Existing GST-registered businesses with total annual supplies of S$4,000,000 or less |
| 1 April 2031 | Existing GST-registered businesses with total annual supplies above S$4,000,000 |
If the e-invoicing requirement applies to you
Total annual supplies means your Box 4 totals for the GST return periods ending in calendar year 2025, and IRAS has been notifying businesses registered before 2026 of their date since mid-2026. When your date comes:
- Choose a solution from IMDA's list of accredited e-invoicing solutions (free-of-charge packages are listed too), or connect your own system through an IMDA-accredited Access Point provider.
- Your provider registers your business with its UEN in Singapore's e-invoicing directory, which gives you an e-invoicing ID.
- Turn on the solution's GST e-invoice submission, so invoice data goes to IRAS.
- Send data for the standard-rated, zero-rated and exempt supplies and the purchases in your GST return, by the earlier of the day you file the return or its due date.
Where AQUORIA O.N.E helps, and where it doesn't
Set your GST rate, your GST registration number and whether your prices include GST. Your receipts and A4 invoices then show your registration number and the GST, and are titled 'Tax invoice' when you're registered and charge GST. Expenses record the GST included, with a photo of the receipt.
Each quarter, the Tax & accounting tab in Finance lays out your figures in the order of the GST F5 boxes: standard-rated supplies, zero-rated and exempt supplies, total supplies, taxable purchases, output tax, input tax and the net GST to pay. Adjustments such as bad debt relief and imports aren't included, so check with your accountant before filing. The invoice list and sales download as CSV files on every plan.
AQUORIA O.N.E is not an accredited e-invoicing solution and doesn't send invoice data to IRAS. When the requirement applies to you, you submit through an e-invoicing solution from IMDA's accredited list.
How it works
- 1In Settings, enter your GST rate and registration number, and say whether your prices include GST.
- 2Take orders and send receipts and A4 invoices; registered shops' documents are titled 'Tax invoice'.
- 3Record expenses with the GST included and a photo of each receipt.
- 4At the end of each quarter, open Finance, then Tax & accounting, check the F5 figures with your accountant, and file on myTax Portal.
What you'll use
- InvoicingInvoice software for Singapore: receipts and A4 invoices with GST, numbering, payment terms, PayNow QR, statements and reminders. Free for 14 days.
- AccountingAccounting software for Singapore: expenses and profit, bills to pay, bank matching from your statement, GST F5 figures and CSV exports. Try it free.
- Point of saleA POS system for Singapore on the phone, tablet or computer you own: quick sales, walk-ins, PayNow QR, receipts and cash-up. No hardware. Try it free.
- ReportsSales report software with a live dashboard: revenue by day, service and channel, payments by method, top customers and CSV downloads. Try it free.
Plan: Essential or Business
Sources
- IRAS: Do I need to register for GST?
- IRAS: Factors to consider before registering voluntarily for GST
- IRAS: GST InvoiceNow Requirement
- IRAS: Invoicing customers
- IRAS: Preparing for the GST rate change (price display)
- IRAS: Late filing or non-filing of GST returns (F5/F8)
- IRAS: e-Tax Guide, How do I prepare my GST return
- IRAS: What is unauthorised GST collection
Published 4 November 2026
Questions
What is the GST registration threshold in Singapore?
S$1 million of taxable turnover. You must register if it was more than S$1 million in a calendar year (apply by 30 January and you're registered from 1 March), or if you reasonably expect more than S$1 million in the next 12 months (apply within 30 days of that forecast). Exempt supplies and sales of capital assets don't count towards it.
Can I register for GST voluntarily?
Yes, below the S$1 million threshold, if you meet IRAS's conditions. You must stay registered for at least two years, so weigh the input tax you'd claim against the admin and the GST your customers would pay. From 1 April 2026, new voluntary registrants must also send invoice data to IRAS through an IMDA-accredited e-invoicing solution.
Can I charge GST if I'm not GST-registered?
No. Only GST-registered businesses may charge and collect GST, and issuing invoices that charge GST without being registered is an offence, with penalties of up to three times the GST collected and a fine. Until IRAS registers you, keep GST off your prices, receipts and invoices. AQUORIA O.N.E adds GST only once you set a rate.
Is GST e-invoicing mandatory in Singapore?
For GST-registered businesses, in phases. It already applies to new voluntary registrants from 1 April 2026, then to new compulsory registrants and existing registrants with annual supplies up to S$200,000 from 1 April 2028, and to everyone else by 1 April 2031. IRAS has written to businesses registered before 2026 with their date.
How often do I file GST returns?
Usually every quarter. New registrants get three-month accounting periods unless they ask otherwise, and each GST F5 return and its payment are due one month after the period ends, so a July to September return is due by 31 October. File a nil return even for a quarter with no sales; a late return costs S$200 straight away.