Goods and Services Tax (GST) is one of the most significant tax obligations for Singapore businesses. Whether GST registration is mandatory or voluntary depends on your company’s annual taxable turnover — and getting the timing wrong can expose your business to back-taxes, penalties, and interest charges from IRAS.

This guide covers the 2026 rules for GST registration in Singapore: who must register, when the obligation kicks in, how to apply, what happens after registration, and the most common mistakes businesses make.

What Is GST and the Current Rate?

GST is a broad-based consumption tax levied on the supply of goods and services in Singapore, as well as on imports. It is governed by the Goods and Services Tax Act (Cap. 117A). The current GST rate is 9%, which took effect on 1 January 2024 (raised from 8%). This rate applies to most standard-rated supplies. Zero-rated supplies (such as exports and international services) are taxed at 0%. Exempt supplies (such as financial services and residential property) are not subject to GST.

Who Must Register for GST in Singapore?

GST registration is mandatory when a business exceeds the registration threshold of S$1 million in annual taxable turnover. IRAS applies two triggers:

1. Retrospective Basis (Looking Back)

If your taxable turnover for the past 12 months (assessed at the end of each calendar quarter) has exceeded S$1 million, you are required to register for GST. The obligation to register arises at the end of that 12-month period, and registration must be submitted within 30 days. IRAS will then make you a GST registrant from the first day of the third month after your application.

Example: If your turnover for the 12 months ending 31 March 2026 exceeds S$1 million, you must apply by 30 April 2026. IRAS will register you from 1 June 2026.

2. Prospective Basis (Looking Forward)

If there are reasonable grounds to expect your taxable turnover in the next 12 months to exceed S$1 million, you must register for GST before that threshold is crossed. This commonly arises when you sign a large contract or receive a purchase order that will push your revenue above the threshold.

Under the prospective basis, registration takes effect from the date you were required to be registered (or from an earlier agreed date). This means IRAS may require you to account for GST retrospectively on supplies made before your registration was formalised — a significant financial risk if you have not been collecting GST from customers.

Voluntary GST Registration

Businesses with taxable turnover below S$1 million may voluntarily register for GST. This is common for businesses that make significant GST-bearing purchases and want to claim input tax credits, or for those seeking to project a more established profile to commercial counterparties.

Voluntary registrants must remain registered for at least two years and comply with all GST filing and record-keeping obligations throughout. IRAS may impose conditions on voluntary registrants, including requiring a banker’s guarantee or security deposit.

How to Apply for GST Registration

GST registration is done through IRAS’s myTax Portal. The process involves:

  1. Log in to myTax Portal using your Singpass or CorpPass
  2. Submit the GST F1 application — this includes details of your business, expected or actual taxable turnover, and the basis for registration (mandatory or voluntary)
  3. Upload supporting documents — typically recent financial statements, a business profile from ACRA, and evidence of taxable supplies
  4. Await IRAS approval — IRAS typically processes applications within 10 working days for straightforward cases
  5. Receive your GST registration number — once approved, you will receive confirmation of your registration date and GST number

Your company secretary can assist with obtaining the relevant ACRA documents and preparing the supporting package for submission. For a broader view of Singapore tax compliance obligations, see our Singapore company compliance calendar.

What Happens After GST Registration?

Once registered, your business must:

  • Charge GST at 9% on all standard-rated supplies made to customers in Singapore
  • Issue valid tax invoices that include your GST registration number and the GST amount charged
  • File GST returns on a quarterly basis (or monthly, for high-turnover businesses) via myTax Portal, accounting for output tax collected and input tax claimable
  • Maintain GST records for at least five years, including invoices, receipts, contracts, and import documents
  • Remit net GST to IRAS by the due date (one month after the end of each accounting period)

A late filing penalty of S$200 is imposed for each GST return not submitted on time. Unpaid GST attracts a 5% late payment penalty, plus 1% per month on the outstanding amount.

InvoiceNow: Mandatory for GST-Registered Businesses

Since January 2025, all newly registered GST businesses must transmit invoices to government agencies via InvoiceNow, Singapore’s nationwide e-invoicing network based on the Peppol standard. Existing GST registrants not yet onboarded to InvoiceNow should do so as the network continues to expand across the private sector. IRAS has confirmed that InvoiceNow adoption will be progressively mandated for all GST-registered businesses.

Your accounting software or cloud ERP should support Peppol-compliant e-invoicing. If you need help reviewing your accounting setup, our corporate services team can assist — or see our article on Singapore payroll and CPF employer obligations for related compliance context.

Reverse Charge and Overseas Vendor Registration

Two special GST regimes apply to imported services and digital goods:

  • Reverse charge mechanism: Since 1 January 2020, GST-registered businesses that receive imported services (such as overseas legal advice, software licences, or cloud services) from foreign vendors must account for GST on those services themselves, even if the foreign vendor does not charge GST. This is known as self-accounting or reverse charge.
  • Overseas Vendor Registration (OVR): Since 1 January 2020, foreign suppliers of B2C digital services to Singapore consumers must register for GST in Singapore if their global turnover exceeds S$1 million and they have more than S$100,000 in supplies to Singapore consumers.

GST Deregistration

A GST-registered business must apply to deregister if its taxable turnover drops below S$1 million for two consecutive years, or if the business ceases to make taxable supplies. Voluntary deregistration requires at least two years of registration. Failure to deregister when obligated can result in ongoing compliance obligations and penalties.

Common GST Registration Mistakes

The most frequent errors IRAS identifies include registering too late (especially under the retrospective basis), treating exempt supplies as taxable supplies (inflating apparent turnover), failing to account for GST on imported services under reverse charge, incorrectly claiming input tax on non-business expenses, and not maintaining adequate records to support GST returns.

If you need legal or tax advice on GST compliance or a dispute with IRAS, engaging a qualified adviser early can prevent a straightforward compliance issue from escalating. For useful Singapore business and regulatory news, business owners can stay informed on tax and compliance updates. Beyond tax compliance, sound financial and investment planning supports long-term business resilience.

To speak with the team at Raffles Corporate Services, you can email [email protected] or call, SMS, or WhatsApp +65 8501 7133. We are happy to assist with any queries.

— The Editorial Team, Raffles Corporate Services