When does a Singapore business have to register for GST?
A Singapore business must register for GST when its taxable turnover is more than S$1 million, either for the calendar year just ended or as reasonably expected in the next 12 months. On the calendar year view, apply between 1 and 30 January and registration starts on 1 March. On the forecast view, apply within 30 days; registration takes effect 2 months after the forecast date.
GST registration is one of the few tax obligations that arrives in the middle of the year, often the day a big contract is signed. Miss it and IRAS backdates the registration, so the GST on those sales comes out of your margin. The test is simple once you know which turnover counts and which of IRAS's two views applies.
The rule stated plainly
A business must register for GST if its taxable turnover is more than S$1 million on either of two views. The current GST rate is 9%.
Retrospective view
Add up taxable turnover for the calendar year, 1 January to 31 December. If it exceeded S$1 million, apply for registration between 1 and 30 January of the following year. Registration takes effect on 1 March of that year. IRAS's example: taxable turnover for 2025 above S$1 million, apply 1 to 30 January 2026, registered from 1 March 2026.
Prospective view
If at any time you can reasonably expect taxable turnover to exceed S$1 million in the next 12 months, apply within 30 days of the forecast date. For forecasts on or after 1 July 2025, registration takes effect 2 months after the forecast date. For forecasts before 1 July 2025 it was the 31st day after the forecast.
The forecast must be backed by evidence such as signed contracts, accepted quotations, or income statements showing the past 12 months already close to S$1 million with an upward trend. A forecast based only on sales targets or a business plan does not trigger registration.
| IRAS example (forecast on or after 1 July 2025) | Forecast date | Apply by | Registered from |
|---|---|---|---|
| Contract signed | 1 Jul 2025 | 31 Jul 2025 | 1 Sep 2025 |
| Quotation accepted | 2 Sep 2025 | 2 Oct 2025 | 2 Nov 2025 |
| Projection made | 15 Jan 2026 | 14 Feb 2026 | 15 Mar 2026 |
| Tender secured | 31 Dec 2025 | 30 Jan 2026 | 28 Feb 2026 |
What counts as taxable turnover
Taxable turnover is standard-rated supplies plus zero-rated supplies (such as exports of goods) made in Singapore in the course of business. It excludes exempt supplies, out-of-scope supplies, and sales of capital assets such as machinery, equipment, an office building or furniture. The test is on taxable turnover, not total revenue.
Worked example: a signed contract in November
A private limited company with 2026 sales as below sells an old machine for S$40,000 in June. On 2 November 2026 it signs a contract worth S$1.2 million to be delivered over the next 12 months.
| Month 2026 | Standard-rated | Zero-rated | Taxable turnover | Year to date |
|---|---|---|---|---|
| Jan | 80,000 | 12,400 | 92,400 | 92,400 |
| Feb | 80,000 | 8,100 | 88,100 | 180,500 |
| Mar | 85,000 | 16,300 | 101,300 | 281,800 |
| Apr | 85,000 | 10,600 | 95,600 | 377,400 |
| May | 90,000 | 9,800 | 99,800 | 477,200 |
| Jun (machine sale of 40,000 excluded) | 90,000 | 14,200 | 104,200 | 581,400 |
| Jul | 90,000 | 7,500 | 97,500 | 678,900 |
| Aug | 90,000 | 13,900 | 103,900 | 782,800 |
| Sep | 95,000 | 5,700 | 100,700 | 883,500 |
| Oct | 95,000 | 12,200 | 107,200 | 990,700 |
Retrospective view. Taxable turnover to 31 October is S$990,700, which is not more than S$1 million. The calendar year is not over, so this view cannot be concluded yet. If the full year 2026 exceeds S$1 million, the company would apply between 1 and 30 January 2027 and be registered from 1 March 2027.
Prospective view. The signed contract alone makes taxable turnover reasonably expected to exceed S$1 million in the next 12 months, and it is documented. The forecast date is the contract date, 2 November 2026:
- Apply by: 30 days after 2 November 2026, so 2 December 2026.
- Registered from: 2 months after the forecast date, so 2 January 2027.
The prospective view gives the earlier date, so it governs. From 2 January 2027 the company charges 9% GST on its standard-rated sales.
The zero-rated share here is about 11% of taxable turnover, so the exemption for businesses with more than 90% zero-rated supplies does not apply.
Common mistakes
Testing total revenue instead of taxable turnover
Including the S$40,000 machine sale would have pushed the year to date to S$1,030,700 and suggested a retrospective liability that does not exist. Capital asset sales, exempt supplies and out-of-scope supplies come out first.
Leaving out zero-rated sales
Exports and international services are zero-rated, not exempt. They count towards the S$1 million even though no GST is charged on them.
Waiting for the year end after a big contract
A signed contract, accepted quotation or secured tender starts the 30 day clock on the prospective view. Waiting for January can make the registration late.
Using the old effective date rule
Before 1 July 2025 registration took effect on the 31st day after the forecast. For forecasts from 1 July 2025 it is 2 months after. Older templates and articles still show the 31 day rule.
Treating a sales target as a forecast
IRAS does not require registration on a forecast built only on business plans or sales targets. Re-test when orders are firm and documented.
How the free kit does it
The free GST Registration Checker takes monthly standard-rated and zero-rated sales, builds the taxable turnover table with a running year to date, and tests both the calendar year and any supported 12 month forecast against the S$1 million threshold. It gives the apply-by and effective dates, flags the zero-rated exemption, late registration exposure and voluntary registration in outline, and writes a short memo with every rule referenced to iras.gov.sg.
This article is general reference material and not tax advice. Check the current IRAS guidance for your business before applying, and take advice where supplies are hard to classify.
Frequently asked questions
What is the GST registration threshold in Singapore?
Taxable turnover of more than S$1 million. IRAS tests it two ways: the retrospective view (taxable turnover for the calendar year exceeded S$1 million) and the prospective view (taxable turnover is reasonably expected to exceed S$1 million in the next 12 months). Meeting either one makes registration compulsory.
What counts as taxable turnover for GST registration?
Standard-rated and zero-rated supplies made in Singapore in the course of business. Exempt supplies, out-of-scope supplies and sales of capital assets such as machinery, equipment, office buildings and furniture are left out.
When does GST registration take effect after signing a big contract?
If the contract makes taxable turnover reasonably expected to exceed S$1 million in the next 12 months, apply within 30 days of the contract date. For forecasts on or after 1 July 2025, registration takes effect 2 months after the forecast date. IRAS's example: contract signed 1 July 2025, apply by 31 July 2025, registered from 1 September 2025.
What happens if you register for GST late in Singapore?
IRAS backdates the registration to the date it should have taken effect, and GST is payable on sales from that date even if it was not collected. There can be a fine of up to S$10,000 and a penalty equal to 10% of the GST due. With voluntary disclosure the fine and penalty are generally waived, but the backdated GST is still payable.
Can an exporter be exempt from GST registration?
Yes, if it applies to IRAS and qualifies. A business may be exempted where zero-rated supplies are more than 90% of total taxable supplies and it would be in a net refundable position had it been GST-registered.
Sources
Holly is a Chartered Accountant (Singapore) and ISCA member who runs the finance and corporate services function of a Singapore company. She founded Halynce Advisory and writes every AccountingAI skill from real month-end, payroll and HR work.