Last updated: 13 July 2026
The short answer
GST registration in Singapore becomes compulsory once your taxable turnover crosses S$1 million, measured two ways: what you actually did last calendar year, and what you can reasonably expect in the next 12 months. Either test can trigger it. The current GST rate is 9%. Register late and IRAS backdates you, which means paying GST out of your own pocket on past sales you never charged it on. And since 1 April 2026, anyone registering voluntarily must also plug into InvoiceNow, Singapore's e-invoicing network.
The three facts that matter
- Crossed S$1 million in taxable turnover last calendar year? Apply by 30 January; you're registered from 1 March.
- Expect to cross S$1 million in the next 12 months (a signed contract counts)? Apply within 30 days of that forecast; registration takes effect 2 months later.
- Miss the deadline and IRAS backdates your registration, adds a penalty of 10% of the GST due and a fine of up to S$10,000. Voluntary disclosure usually removes the fine and penalty, never the back tax.
The two tests, in plain terms
The retrospective test looks backwards. At the end of each calendar year, add up your taxable turnover from 1 January to 31 December. Over S$1 million? You must apply for registration by 30 January of the new year, and you are GST-registered from 1 March.
The prospective test looks forwards, and it catches people off guard. If at any point you can reasonably expect taxable turnover to exceed S$1 million in the next 12 months, the clock starts that day. You have 30 days to apply, and for liability arising on or after 1 July 2025, registration takes effect 2 months from the forecast date. "Reasonably expect" means evidence: signed contracts, accepted quotations, confirmed purchase orders.
The tests run at the same time. Sign one large contract in October and the prospective test can make you registrable months before your year-end accounts would have.
What counts as taxable turnover
The S$1 million is taxable turnover, not total revenue. It includes standard-rated sales (9%) and zero-rated sales (0%, mainly exported goods and international services). It excludes exempt supplies such as financial services and residential property rental, and supplies made outside Singapore.
The most common miscalculation runs in both directions: owners either count exempt income and panic early, or forget that zero-rated exports count and register late. Exports are 0% GST, but they still push you toward the threshold.
The deadlines, side by side
| Trigger | Apply by | Registered from |
|---|---|---|
| Retrospective: calendar year exceeded S$1M | 30 January of the following year | 1 March |
| Prospective: 12-month forecast exceeds S$1M | 30 days from the forecast date | 2 months from the forecast date |
GST registration checker
Enter your taxable turnover to see which registration test applies to you.
What late registration actually costs
IRAS backdates your registration to the date you should have registered. From that date, you owe GST on every taxable sale, whether or not you charged your customers a cent of it. On S$1.2 million of backdated sales, that is roughly S$99,000 of output tax (9/109 of the gross) coming out of your margin.
On top of the back tax, IRAS can impose a penalty of 10% of the GST due and a fine of up to S$10,000.
The escape hatch: come forward before IRAS finds you. Under voluntary disclosure, IRAS generally waives the fine and the 10% penalty. The back GST itself is always payable. If you suspect you crossed the threshold in an earlier year, the cheapest moment to fix it is now.
Registering voluntarily below S$1 million
You can register before the law makes you, and sometimes you should. The classic case: your customers are mostly GST-registered businesses (they claim back whatever you charge, so your prices don't really rise) and you have meaningful input tax to recover on rent, equipment or imports.
Voluntary registration carries conditions:
- You must stay registered for at least 2 years.
- GST must be paid by GIRO.
- The director, sole proprietor, partner or trustee must complete the IRAS "Overview of GST" e-learning course before applying, unless they already run another GST-registered business.
If your customers are mostly consumers, think twice. They can't recover GST, so registering makes you 9% more expensive or 9% less profitable. One of the two.
The InvoiceNow rule: the part most 2026 guides miss
InvoiceNow is Singapore's national e-invoicing network, built on the same Peppol standard the UAE is adopting for its own e-invoicing mandate. IRAS is phasing it into GST compliance:
- Since 1 November 2025: newly incorporated companies (within 6 months of incorporation) registering voluntarily must transmit invoice data to IRAS via InvoiceNow.
- Since 1 April 2026: every new voluntary registrant must, regardless of age or structure.
- Announced at Committee of Supply 2026: the requirement extends to all GST-registered businesses by April 2031.
Practical consequence: if you're registering voluntarily now, confirm your accounting software is InvoiceNow-compatible before you apply, not after. Compulsory registrants are not caught yet, but the 2031 date means every Singapore business ends up on the network eventually.
Not sure which side of S$1 million you're on?
Send us your numbers and our Singapore team will confirm whether either test has triggered, and what your dates are. One message, no charge.
Check my positionHow to apply, step by step
- Log in to myTax Portal (mytax.iras.gov.sg) with Corppass.
- Select GST, then "Apply for GST Registration". Declare whether you're registering under the retrospective or prospective test, or voluntarily.
- Attach evidence. ACRA business profile, accounts showing turnover, and for prospective registration the contracts or quotations behind your forecast. Voluntary registrants: GIRO form and the e-learning completion.
- Submit and wait. Straightforward applications are typically processed in about 10 working days. There is no application fee.
Life after registration
From your effective date you charge 9% on standard-rated supplies, file GST F5 returns (quarterly for most businesses) through myTax Portal, and keep records for five years. The late filing penalty is S$200 for each completed month a return is outstanding, capped at S$10,000 per return.
Two special cases worth knowing. Exporters whose supplies are wholly or mostly zero-rated can apply for exemption from registration, which spares them the admin of filing refund-position returns. And overseas businesses selling to Singapore consumers fall under the Overseas Vendor Registration regime once global turnover passes S$1 million and Singapore B2C sales pass S$100,000.
Setting up the invoicing, the chart of accounts and the first F5 correctly is most of the battle. It's the kind of work our accounting and tax team in Singapore does daily, usually alongside incorporation for new entities.
The mistakes we see most
- Watching only the year-end number. The prospective test triggers mid-year, the moment a big contract is signed.
- Counting the wrong turnover. Exempt income doesn't count; zero-rated exports do.
- Sitting on a missed registration. Backdated GST grows every month. Voluntary disclosure caps the damage, waiting compounds it.
- Registering voluntarily with consumer customers. A 9% price disadvantage against unregistered competitors is a real cost, not a formality.
- Applying voluntarily without InvoiceNow-ready software. Required since 1 April 2026.
GST handled end to end
Registration, InvoiceNow setup, quarterly F5 filings and the bookkeeping behind them, run from our Singapore office, with Dubai and India covered from the same team.
Talk to our Singapore teamFrequently asked questions
What is the GST registration threshold in Singapore?
Taxable turnover above S$1 million, measured on either the past calendar year (retrospective test) or a reasonable forecast of the next 12 months (prospective test). Either test alone triggers compulsory registration.
What is the GST rate in Singapore in 2026?
9%, unchanged since 1 January 2024.
How long does GST registration take?
Around 10 working days for straightforward applications through myTax Portal. There is no application fee.
What happens if I register late?
IRAS backdates your registration and you owe GST on past sales from that date, plus potentially a 10% penalty and a fine of up to S$10,000. Coming forward under voluntary disclosure generally gets the fine and penalty waived; the back tax always stands.
Can I register for GST voluntarily below S$1 million?
Yes, if you commit to at least 2 years of registration, pay by GIRO, and complete the IRAS "Overview of GST" e-learning course. Since 1 April 2026, new voluntary registrants must also transmit invoice data to IRAS via InvoiceNow.
Does InvoiceNow apply to all GST-registered businesses?
Not yet. As of mid-2026 it applies to new voluntary registrants. IRAS announced at Committee of Supply 2026 that it will extend to all GST-registered businesses by April 2031.
Do freelancers and sole proprietors have the same threshold?
Yes. All taxable supplies made by the same person are aggregated across income streams, and the same S$1 million tests apply.
Sources
- IRAS: Do I need to register for GST (registration tests, deadlines, effective dates). iras.gov.sg
- IRAS TaxBytes: liability to register and consequences of late registration. iras.gov.sg
- IRAS: GST InvoiceNow Requirement. iras.gov.sg
- IRAS newsroom, Committee of Supply 2026: extension of the InvoiceNow requirement to all GST-registered businesses by April 2031. iras.gov.sg