Goods and Services Tax (GST) registration is one of the most consequential compliance decisions a Singapore business makes. Register too late and you face back-dated tax liabilities plus penalties from the Inland Revenue Authority of Singapore (IRAS). Register voluntarily at the right time and you gain a legitimate mechanism to recover input GST on your business expenses. Fail to comply with the new InvoiceNow requirements introduced from 1 April 2026 and you face additional penalties.

This guide covers everything Singapore business owners need to know about GST registration in 2026 — the two mandatory triggers, how to calculate whether you have crossed the threshold, the voluntary registration calculus, the registration process, and the new InvoiceNow e-invoicing obligations that apply to all new registrants.

What Is GST and What Is the Current Rate?

GST is a broad-based consumption tax levied on the supply of goods and services in Singapore and on the importation of goods into Singapore. The rate was raised from 8 per cent to 9 per cent on 1 January 2024 and remains at 9 per cent in 2026. GST-registered businesses collect GST from their customers, remit the net amount to IRAS (after deducting input GST), and file quarterly GST returns via IRAS myTax Portal.

When Must You Register? The Two Triggers

There are two situations in which a Singapore business is legally required to register for GST:

Trigger 1: Retrospective (Historical Turnover) Basis

At the end of any calendar quarter, if your taxable turnover for the past 12 months has exceeded S$1 million, you are required to register for GST. You must notify IRAS within 30 days of the end of that quarter. Your GST registration takes effect from the first day of the second month following the end of that quarter.

Example: If your cumulative taxable turnover for 1 January 2026 to 31 December 2026 exceeds S$1 million, you must notify IRAS by 30 January 2027. Your registration would take effect from 1 February 2027.

Trigger 2: Prospective (Forward-Looking) Basis

If at any point in time you have reasonable grounds to expect that your taxable turnover for the next 12 months will exceed S$1 million, you must register immediately — notification to IRAS must be made within 30 days, and registration takes effect from the date of notification (or an earlier agreed date).

This forward-looking trigger catches businesses that have just signed a large contract and can reliably forecast that their turnover will cross the threshold within the next year.

What Counts as Taxable Turnover?

Not all revenue counts towards the S$1 million threshold. The turnover that counts is the value of taxable supplies — standard-rated supplies (currently 9%) and zero-rated supplies (0%, e.g., exports of goods and international services).

The following do not count towards the registration threshold:

  • Exempt supplies: Sale or lease of residential properties, financial services (e.g., interest income, dividends from shares held as investments).
  • Out-of-scope supplies: Sale of goods entirely located outside Singapore, private transactions, salary paid to employees.
  • One-off capital asset sales: Proceeds from selling a capital asset (e.g., a piece of machinery) used in your business are generally excluded.

IRAS provides detailed guidance on what constitutes taxable turnover in its GST registration guidance (iras.gov.sg).

Voluntary GST Registration

Even if your taxable turnover is below S$1 million, you may choose to register for GST voluntarily. This can be commercially beneficial if:

  • You incur significant GST on business inputs (rent, imported goods, professional services, advertising, IT systems) and wish to recover that input GST.
  • Most of your customers are GST-registered businesses — they can claim back the GST you charge them, so your GST registration has no net cost to them.
  • You are planning rapid growth and want to avoid the disruption of mandatory registration mid-contract.

Voluntary registration is less attractive if most of your customers are consumers (end-users) who cannot recover GST — in that case, your 9% GST charge effectively raises your prices relative to unregistered competitors.

To be eligible for voluntary registration, your business must be making, or intending to make, taxable supplies. A holding company with only exempt investment income may not qualify.

How to Register for GST

GST registration is done online through the IRAS myTax Portal:

  1. Log in to myTax Portal using your Corppass (for company registrations) or Singpass (for sole proprietors).
  2. Under “GST”, select “Apply for GST Registration”.
  3. Complete the GST Registration Form (GST F1), providing details of your business, estimated annual taxable turnover, nature of supplies, and anticipated registration date.
  4. IRAS typically processes straightforward applications within 3 to 5 working days. More complex applications may take up to 10 working days.
  5. Upon successful registration, IRAS issues a GST registration number. You must display this number on all tax invoices issued to your customers.

The InvoiceNow Requirement for New Registrants (From 1 April 2026)

One of the most significant changes affecting new GST registrants in 2026 is the mandatory adoption of InvoiceNow — Singapore’s government-mandated e-invoicing network based on the international Peppol standard.

Who Must Comply?

  • New mandatory registrants whose taxable turnover threshold is exceeded on or after 1 April 2026: InvoiceNow compliance is required from the effective date of GST registration.
  • New voluntary registrants applying for GST registration on or after 1 April 2026: InvoiceNow compliance is required from the effective date of registration.
  • Existing registrants are subject to a phased implementation — IRAS has set different compliance dates for different business sizes. Large businesses (annual turnover above S$10 million) had earlier deadlines; smaller businesses have later ones.

What Does InvoiceNow Mean in Practice?

InvoiceNow requires businesses to transmit structured invoice data electronically through an IRAS-approved network access point (essentially an accredited e-invoicing software provider). The invoice data is transmitted in a standardised XML format (UBL 2.1). This does not mean you must stop issuing PDF invoices — you can continue to do so for customer-facing purposes — but the underlying invoice data must also be transmitted through InvoiceNow.

Approved InvoiceNow network access points are listed on the IMDA website. Many popular Singapore accounting software packages (including QuickBooks, Xero, and Sage) have already integrated InvoiceNow compliance. See our dedicated guide to the GST InvoiceNow requirement for a step-by-step implementation checklist.

Consequences of Not Registering on Time

Late GST registration carries serious financial consequences:

  • Back-dated liability: IRAS will deem your registration effective from the date you should have registered. You become liable to remit GST on all taxable supplies made since that date — even if you did not collect GST from your customers.
  • Penalties: Under Section 48 of the GST Act, late registration attracts a fine of up to S$10,000 and/or imprisonment of up to 7 years.
  • Interest: Outstanding GST amounts attract interest at the prescribed rate.

If you believe you should have registered earlier and did not, voluntary disclosure to IRAS before they discover the error is strongly recommended — IRAS typically treats voluntary disclosures more leniently.

GST Deregistration

If your taxable turnover falls below S$1 million and you are no longer making taxable supplies, you may apply to cancel your GST registration. Cancellation requires IRAS approval and involves filing a final GST return. Note that you cannot cancel registration for at least two years after voluntary registration, unless you cease to make taxable supplies entirely.

Getting GST Registration Right

GST registration, quarterly filing, and InvoiceNow compliance are manageable with the right accounting infrastructure and professional support. If you are approaching the S$1 million threshold — or already past it — acting quickly to register correctly protects you from avoidable penalties.

For assistance with GST registration, quarterly GST filing, InvoiceNow implementation, and broader bookkeeping and tax compliance, contact Raffles Corporate Services.

— The Editorial Team, Raffles Corporate Services