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Answers · GST · registration is compulsory over S$1,000,000 of taxable turnover

Do I have to register for GST, and from when?

You must register once your taxable turnover passes S$1,000,000, tested two ways. Looking back: if it is over S$1,000,000 for a calendar year, apply by 30 January of the next year and you are registered from 1 March: for the year you are in, ending 31 Dec 2026, apply by 30 Jan 2027 and you are registered from 1 Mar 2027 (for the year that ended 31 Dec 2025, the application was due by 30 Jan 2026 and registration took effect on 1 Mar 2026). Looking forward: on the day you can reasonably expect it to pass S$1,000,000 in the next 12 months, apply within 30 days, and you are registered 2 months from that day: if the forecast is made today, 9 Sep 2026, you are registered from 9 Nov 2026.

Under S$1,000,000 on both tests, registration is voluntary, with one exception. A business that cannot claim its input tax in full, because it makes exempt supplies or holds investments for dividend income, can be liable to register on the imported services and low-value goods it buys alone, whatever its taxable turnover. That is a second route in, with its own threshold, and it is not the one worked on this page. See who reverse charge reaches, and what box 14 is. Once in, you stay in for at least 2 years.

Rulebook figures, timing checked by hand Edition YA-2027 · sources verified through 24 Jul 2026

The threshold, and what counts towards it

The line is S$1,000,000 of taxable turnover. Taxable turnover is your standard-rated supplies and your zero-rated supplies added together: sales to Singapore customers that carry GST at 9%, and exports and international services at 0%. It leaves out exempt supplies (residential rent, most financial services), supplies outside the scope of GST, and the sale of capital assets such as a van or a machine.

So a company can take in more than S$1,000,000 and still be under the threshold, and a company whose sales are all exports, on which it charges no GST, can be over it. The figure to watch is the sales themselves, not what is in the bank.

The two tests, and the date each one gives

Looking back: taxable turnover over S$1,000,000 for the calendar year. Looking forward: at any point you can reasonably expect to exceed S$1,000,000 in the next 12 months. Each test has its own application window and its own effective date, and the effective date is the day you start charging GST.

TestMeasured overYou cross itApply byRegistered from
Retrospectivelooking backTaxable turnover for one calendar year, 1 January to 31 December, over S$1,000,000On 31 December of that year30 January of the following year1 March of the following year
Prospectivelooking forwardTaxable turnover you can reasonably expect in the next 12 months, over S$1,000,000On the day the expectation becomes reasonableWithin 30 days of that day2 months from that day (liability arising on or after 1 Jul 2025)

The two tests run at the same time. The retrospective one is a single check at the end of every calendar year; the prospective one can fire on any day, and a company under the threshold at 31 December can still be caught by a contract signed in March.

The retrospective test: the calendar year that ended 31 Dec 2025

At 31 December, add up the taxable turnover for that calendar year. Over S$1,000,000, you apply between 1 and 30 January and you are registered on 1 March. That is the rule itself, not a concession on an earlier date: nothing is backdated to 1 January, and the two months in between are yours to get ready in.

For the year that ended 31 Dec 2025 the application was due by 30 Jan 2026 and registration took effect on 1 Mar 2026. For the year you are in now, ending 31 Dec 2026, the same test gives 30 Jan 2027 and 1 Mar 2027.

The test is over the calendar year, not your financial year, so a company with a June year end still counts January to December for this purpose.

The prospective test: the next 12 months

On any day, if you can reasonably expect your taxable turnover in the next 12 months to pass S$1,000,000, that day is the day you become liable. Reasonably expect means an expectation you can show, supported by signed contracts or accepted quotations. A speculative forecast does not start the clock.

From that day you have 30 days to apply, and you are registered 2 months from that day. A forecast made today, 9 Sep 2026, must be applied for by 9 Oct 2026 and takes effect on 9 Nov 2026.

The 2-month timing applies to a liability arising on or after 1 Jul 2025. Before that date the rule was the 31st day after the forecast; a liability that arose earlier took the earlier date.

Two companies, one crossing on each test

Worked

Company A crosses looking back, Company B crosses looking forward

CompanyTestFigureCrossed onApply byRegistered from
Company AretrospectiveTaxable turnover for calendar 20251,125,000.0031 Dec 202530 Jan 20261 Mar 2026
Company BprospectiveExpected taxable turnover, next 12 months from 9 Sep 20261,080,000.009 Sep 20269 Oct 20269 Nov 2026

Company A is a trading company with a December year end. Its 2025 receipts came to S$1,167,000.00, but two of the lines do not count: the rent is an exempt supply and the van is a capital asset. Its taxable turnover for the calendar year is S$1,125,000.00, over S$1,000,000 by S$125,000.00. It crossed on 31 Dec 2025, had to apply by 30 Jan 2026, and has been registered since 1 Mar 2026: every standard-rated sale from that day carries GST at 9%.

Company A, calendar year 2025: what counts
ReceiptsCounts?S$
Standard-rated sales to local customersYes, taxable1,030,000.00
Exports, zero-ratedYes, taxable at 0%95,000.00
Rent from a residential flat the company ownsNo, an exempt supply24,000.00
Sale of the old delivery vanNo, a capital asset18,000.00
Taxable turnover for the year1,030,000.00 + 95,000.001,125,000.00

Company B did not cross looking back: its taxable turnover for 2025 was S$640,000.00. Its sales run at S$55,000.00 a month, S$660,000.00 a year, still under. Today, 9 Sep 2026, it signs a S$420,000.00 contract to be delivered over the next 12 months. With the run rate, it can now reasonably expect S$1,080,000.00 in the next 12 months, so today is the day it becomes liable: it applies by 9 Oct 2026 and is registered from 9 Nov 2026.

Company B, the next 12 months from 9 Sep 2026
Expected taxable turnoverArithmeticS$
Standard-rated sales at the current run rate55,000.00 a month × 12660,000.00
The contract signed today, delivered over the 12 months420,000.00
Reasonably expected in the next 12 months660,000.00 + 420,000.001,080,000.00

The liability arose today, whatever the 31 December check shows later. Had Company B waited for that check, it would have been registered late, and the GST due on the sales from 9 Nov 2026 would have come out of its own pocket.

Registering before you have to

You may register below the threshold, usually to claim input tax back. It is a commitment: two years minimum, GIRO, and IRAS has to approve you. Any business making taxable supplies may apply, and approval is discretionary.

Before IRAS approves a voluntary registration, the director or the person who will prepare the returns completes IRAS's e-learning course on GST (waived for someone already running another registered business or an accredited tax practitioner), the business signs up for GIRO, and IRAS may ask for a guarantee. Once in, the registration binds you for at least 2 years, on GIRO throughout, and, since 1 Apr 2026, brings the InvoiceNow requirement with it from the day you register, as a condition of the registration. See InvoiceNow: who is mandated, and from when.

Late, and coming back out

Registering late: a fine of up to S$10,000 and 10% of the GST due from the date you should have been registered. IRAS backdates you to the day you should have been registered, so the GST on every sale since then is due whether you charged it or not, out of your own pocket.

Coming out is deregistration. It is compulsory if you stop trading or stop being liable, and optional once you have fallen below S$1,000,000, subject to conditions. You apply to cancel within 30 days of ceasing to be liable to be registered, a window Simpler Tax's compliance reference cites from secondary sources rather than from the IRAS page itself, so confirm it there; the penalty for missing that window is a fine of up to S$10,000.

Do it in Simpler Tax

Your own calendar year, read from the books

Simpler Tax's Atlas asks the retrospective test with your own figure in it: it adds up the revenue posted for the calendar year just ended and, if that is over S$1,000,000, tells you the compulsory registration and the January window, leaving you only the question no ledger can answer, how much of it was exempt supplies or capital assets. Under the threshold, it says so as far as the books go and leaves the forward forecast, which is yours alone. The first-run screen prints the threshold and the two tests beside the question of whether you are registered. Simpler Tax files nothing and applies for nothing.

Download for Windows Simpler-Tax_1.0.0_x64-setup.exe · 55 MB · not signed yet · free · SHA-256 on the home page

Questions people ask

What counts as taxable turnover?

Your standard-rated and zero-rated supplies added together: local sales that carry GST and exports and international services at 0%. Exempt supplies (residential rent, most financial services), supplies outside the scope of GST and the sale of capital assets are left out. Company A's S$1,167,000.00 of receipts is S$1,125,000.00 of taxable turnover.

Is the S$1,000,000 measured over any 12 months, or over a calendar year?

Two ways, and only two. Looking back, it is the calendar year, 1 January to 31 December, tested once at 31 December. Looking forward, it is the next 12 months from any day on which you can reasonably expect to cross, and that day can fall at any point in the year.

I crossed S$1,000,000 in 2025. From when do I charge GST?

From 1 Mar 2026. The application was due by 30 Jan 2026; applying late does not move that date, it adds the late-registration penalty, a fine of up to S$10,000 and 10% of the GST due from the date you should have been registered. Registration on the retrospective test takes effect on 1 March of the year after the one in which you crossed; you do not charge GST on the January and February in between, and nothing is backdated into 2025.

What if the forecast is only a hope?

The prospective test asks what you can reasonably expect, supported by signed contracts or accepted quotations, not a forecast you would like to come true. A pipeline of unsigned quotes does not start the clock; a signed contract that, with your run rate, takes the next 12 months over the threshold does.

What happens if I register late?

A fine of up to S$10,000 and 10% of the GST due from the date you should have been registered. IRAS backdates you to the date you should have been registered, so the GST on every sale since then is due whether or not you charged it.

Can I register while I am still under S$1,000,000?

Yes. You may register below the threshold, usually to claim input tax back. It is a commitment: two years minimum, GIRO, and IRAS has to approve you. Any business making taxable supplies may apply; approval is discretionary. Before applying, the person responsible for the returns completes IRAS's e-learning course on GST, and the business signs up for GIRO. Since 1 Apr 2026 a voluntary registration also carries the InvoiceNow requirement from the day you register, as a condition of the registration.

My turnover has fallen back under S$1,000,000. Can I cancel?

Yes, by deregistering. It is compulsory if you stop trading or stop being liable, and optional once you have fallen below S$1,000,000, subject to conditions. You apply to cancel within 30 days of ceasing to be liable to be registered, a window Simpler Tax's compliance reference cites from secondary sources rather than from the IRAS page itself, so confirm it there; the penalty for missing that window is a fine of up to S$10,000. A business that registered voluntarily stays in for at least 2 years first.

Sources

Statutory figures on this page are read from the Simpler Tax rulebook at build time, edition YA-2027, every source last checked 24 Jul 2026. The rulebook entries named below are the ones this page was computed from; the IRAS pages are what they were verified against.