Free tool · checked 3 October 2026

GST registration threshold checker for Singapore

Test taxable turnover against the S$1 million GST threshold under IRAS’s calendar-year and next-12-months tests, and see the dates to apply and to be registered. Where IRAS’s pages are silent, the tool says to ask IRAS.

1. Calendar-year test: what was taxable turnover for 1 January to 31 December?

Calendar year

Business or income stream (a name for your own reference)Taxable turnover for the year (S$)

Combined taxable turnover: S$980,000.00

2. Forward-looking test: what do you expect over the next 12 months?

Taxable turnover you expect over the next 12 months (S$)What supports that forecast?Date of the forecast (for example, the day the contract was signed)

The forward-looking (prospective) test is triggered.

Calendar-year test

Taxable turnover for 1 January to 31 December 2026 is not more than S$1 million, so the calendar-year test is not triggered.

Forward-looking test

Date of the forecast: Monday 2 November 2026
Apply within 30 days after it, by: Wednesday 2 December 2026
Registered on: Saturday 2 January 2027

IRAS registers a forecast on or after 1 July 2025 2 months from the forecast date.

If the last day to apply has already passed, IRAS says late notification backdates your registration to the date you ought to have registered, you must account for GST on past sales from then even if you did not charge it, and a fine of up to S$10,000 and a penalty of 10% of the GST due can apply. IRAS says it will generally waive the fine and penalty if you disclose that you are late when you apply. Ask IRAS.

Tests taxable turnover (without exempt supplies, out-of-scope supplies and sales of capital assets) against more than S$1 million, using IRAS’s two views. Combine only the businesses IRAS says to combine. IRAS’s exceptions, the reverse charge and overseas vendor regimes and voluntary registration are not assessed.

Rates and rules this tool uses

The S$1 million threshold and the two views: You must register for GST if your taxable turnover is, under the retrospective view, more than $1 million at the end of the calendar year, or, under the prospective view, expected to be more than $1 million in the next 12 months. IRAS: do I need to register for GST, read 3 October 2026 (page says “Last updated 15 September 2026”).
Retrospective view: dates: Assess taxable turnover for 1 Jan to 31 Dec. If it exceeded $1 million, apply between 1 Jan and 30 Jan of the following year; registered on 1 Mar of that year. IRAS’s example: 2025 turnover above $1 million, apply 1 to 30 Jan 2026, registered 1 Mar 2026. If turnover passed $1 million during the year and you do not reasonably expect more than $1 million in the next 12 months, you are not required to register immediately: wait for the year end or register voluntarily. IRAS: do I need to register for GST, read 3 October 2026 (page says “Last updated 15 September 2026”).
Prospective view: dates: Apply within 30 days after the date of your forecast. Registered on the 31st day after the forecast date if the forecast is before 1 Jul 2025, and 2 months from the forecast date if it is on or after 1 Jul 2025. IRAS prints nine dated examples. IRAS: do I need to register for GST, read 3 October 2026 (page says “Last updated 15 September 2026”).
Two-month grace period: Businesses registering under the prospective view get a two-month grace period to begin charging GST if the date of forecast is on or after 1 Jul 2025, an extension from the previous one-month period. The 30-day application deadline is unchanged. IRAS taxBytes: extended grace period under the prospective basis, read 3 October 2026 (page says “Last updated 24 September 2025”).
Evidence for a forecast: You must have supporting documents, for example signed contracts or agreements, accepted quotations or confirmed purchase orders, invoices with a fixed monthly fee, or income statements showing the past 12 months already close to $1 million with turnover on an increasing trend. You are not required to register if there is no certainty in your forecast, for example one based on market assessment, business plans or sales targets. IRAS: do I need to register for GST, read 3 October 2026 (page says “Last updated 15 September 2026”).
Late notification: Registration is backdated to the date you ought to have been registered, and you must account for and pay GST on past sales from then, even if you did not collect it. You may face a fine of up to $10,000 and a penalty of 10% of the GST due; prosecution action may apply. If you voluntarily disclose that you are late when you apply, IRAS will generally waive the fine and penalties. IRAS: do I need to register for GST, read 3 October 2026 (page says “Last updated 15 September 2026”).
What counts as taxable turnover: The total value of taxable supplies made in Singapore in the course or furtherance of business: standard-rated and zero-rated supplies. It excludes exempt supplies, out-of-scope supplies and sales of capital assets. IRAS: do I need to register for GST, read 3 October 2026 (page says “Last updated 15 September 2026”).
Whose turnover is combined: Sole proprietors combine all their sole proprietorship businesses and trade or vocation income; partnerships combine businesses with the same partners; a company counts its own turnover plus any sole proprietorships it owns. IRAS’s example: $500,000 + $490,000 + $30,000 = $1,020,000. IRAS: do I need to register for GST, read 3 October 2026 (page says “Last updated 15 September 2026”).

Next review: IRAS’s do-I-need-to-register page before each January filing window and whenever IRAS announces a change to the threshold, the 30-day deadline or the 2-month grace period; also recheck whether IRAS addresses weekend deadlines or defines “close to $1 million”. General information, not tax, legal or financial advice.

When must a business register for GST in Singapore?

Registration is compulsory if taxable turnover is more than S$1 million at the end of a calendar year, or if you can reasonably expect it to be more than S$1 million in the next 12 months, says IRAS’s page on whether you need to register. IRAS calls these the retrospective and prospective views. The checker tests both and gives the dates. On our reading of “more than”, exactly S$1,000,000 triggers neither test.

How does the calendar-year test work?

Add up taxable turnover for 1 January to 31 December. If it is more than S$1 million, apply between 1 and 30 January of the following year; you are registered on 1 March. IRAS’s example uses 2025: apply from 1 to 30 January 2026, registered 1 March 2026. The same pattern for 2026 gives 1 to 30 January 2027 and 1 March 2027 (our arithmetic). If turnover passes S$1 million mid-year but you do not reasonably expect more than S$1 million over the next 12 months, IRAS says you need not register immediately.

How does the next-12-months test work?

If at any point you can reasonably expect more than S$1 million in the next 12 months, apply within 30 days after the date of your forecast. For a forecast on or after 1 July 2025 you are registered 2 months from that date, after IRAS’s two-month grace period change. Before then it was the 31st day, so a 1 July 2024 contract was registered on 1 August 2024. IRAS’s printed examples for the new rule include:

1 July 2025 contract: apply by 31 July 2025; registered 1 September 2025.
Forecast on 15 January 2026 after turnover rose 15%: apply by 14 February 2026; registered 15 March 2026.
31 December 2025 tender: apply by 30 January 2026; registered 28 February 2026 (31 December 2027: 30 January 2028 and 29 February 2028).

IRAS says you must hold documents supporting the forecast, such as signed contracts, accepted quotations or orders, fixed-fee invoices or income statements already close to S$1 million, and that you need not register if there is no certainty in your forecast, for example one based on a market assessment, business plans or sales targets. If a last day to apply has passed, IRAS says registration is backdated and a fine of up to S$10,000 and a penalty of 10% of the GST due can apply.

What counts as taxable turnover, and whose turnover is added up?

Taxable turnover is standard-rated plus zero-rated supplies made in Singapore, without exempt supplies, out-of-scope supplies or sales of capital assets, so total sales can overstate it. A sole proprietor adds all their sole proprietorships and trade income: IRAS’s example of S$500,000 + S$490,000 + S$30,000 is S$1,020,000. Partnerships with the same partners are combined, and a company counts its own turnover plus any sole proprietorships it owns. The tool only adds the lines you enter.

What does this checker not do?

Where IRAS’s pages are silent it says to ask IRAS: they do not say whether a weekend deadline moves (30 January 2027 is a Saturday), how the two views combine when both apply, or what “close to $1 million” means, and they print the month-end rule only for forecasts on 31 December. The tool does not assess the exemption for mostly zero-rated suppliers, IRAS’s listed circumstances for not registering, the reverse charge and overseas vendor regimes, or voluntary registration. Our guides cover when to register, GST on quotes and invoices and InvoiceNow.

Common questions

Do I have to register for GST when my sales pass S$1 million?

IRAS tests taxable turnover, not sales: more than S$1 million at a calendar year-end, or reasonably expected over the next 12 months.

How long do I have to apply for GST registration?

Between 1 and 30 January of the following year under the calendar-year test, and within 30 days after the date of your forecast under the next-12-months test.

Can I wait until the year ends if turnover passes S$1 million part-way through?

IRAS says you can if you do not reasonably expect more than S$1 million over the next 12 months, then apply between 1 and 30 January or register voluntarily.

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Sources

IRAS’s page on whether you need to register (iras.gov.sg)
two-month grace period change (iras.gov.sg)
exemption for mostly zero-rated suppliers (iras.gov.sg)