Goods and Services Tax (GST) is a broad-based consumption tax levied at a rate of 9% on the supply of goods and services in Singapore and on imports of goods. For Singapore business owners and directors, understanding when GST registration is required — and when it may be advantageous even if not compulsory — is a fundamental part of managing your company’s tax obligations.

This guide explains the GST registration rules in Singapore, covering compulsory registration thresholds, voluntary registration, the advantages and disadvantages of being GST-registered, the InvoiceNow requirements that apply to new registrants in 2026, and how to apply for registration with the Inland Revenue Authority of Singapore (IRAS).

What is GST?

GST is a value-added tax charged on the sale of most goods and services in Singapore. Registered businesses collect GST from their customers (output tax) and may claim back the GST they pay on their own business purchases (input tax). The difference between output tax collected and input tax paid is remitted to IRAS on a quarterly basis.

The current GST rate is 9%, which has applied since 1 January 2024 (increased from 8% in 2023). Unlike corporate income tax, which is levied on profits, GST is a transaction-level tax — it applies to each taxable supply regardless of whether the company is profitable.

Compulsory GST Registration: The S$1 Million Threshold

Your business is legally required to register for GST if its taxable turnover exceeds S$1 million in the past 12 months, or if you have reasonable grounds to expect that your taxable turnover will exceed S$1 million in the next 12 months.

Taxable turnover refers to the value of taxable supplies made in Singapore (standard-rated at 9% and zero-rated at 0%). It does not include exempt supplies (such as financial services and residential property rentals).

Retrospective Basis (Past 12 Months)

If your taxable turnover exceeds S$1 million in any calendar quarter and the preceding three quarters combined, you must apply for GST registration within 30 days of the end of that quarter. IRAS will then register you with effect from the first day of the third month after the end of that quarter.

Prospective Basis (Next 12 Months)

If you reasonably expect your taxable turnover to exceed S$1 million in the next 12 months, you must apply within 30 days of forming that reasonable expectation. You will be registered from the 31st day after the date of that forecast — though businesses with liability arising on or after 1 July 2025 receive a two-month grace period before they are required to start charging GST.

Important: Failing to register on time can be costly. IRAS may backdate your GST registration and require you to account for GST on past sales — even if you did not collect it from your customers at the time. The GST must come out of your own pocket in such circumstances, along with potential late registration penalties.

Voluntary GST Registration

Businesses below the S$1 million threshold may choose to register voluntarily for GST. This is entirely optional, but it can be advantageous in certain circumstances.

Why Register Voluntarily?

  • Claim input tax credits: As a GST-registered business, you can recover the 9% GST you pay on qualifying business purchases — rent, professional fees, equipment, office supplies — by claiming input tax from IRAS. For businesses with significant overhead expenses but modest revenue (e.g., startups or capital-intensive businesses), this can result in meaningful cash savings.
  • Appear more established: Some corporate buyers prefer to transact with GST-registered suppliers, particularly larger companies who can themselves claim the input tax on purchases.
  • Plan ahead: If your revenue is growing steadily toward the S$1 million threshold, voluntary registration lets you build internal processes and accounting systems before you are legally required to do so.

Drawbacks of Voluntary Registration

  • Compliance burden: GST-registered businesses must file quarterly GST returns with IRAS, maintain detailed records of all taxable supplies and purchases, and issue tax invoices. This adds accounting and administrative overhead.
  • Competitive disadvantage for B2C businesses: If your customers are individuals (not GST-registered businesses), they cannot claim back the GST you charge them. Your prices effectively become 9% more expensive compared to unregistered competitors.
  • Minimum 2-year commitment: Voluntary registrants must remain registered for at least 2 years before applying to deregister. Once registered, you cannot simply opt out if the compliance burden becomes too onerous.

InvoiceNow Requirements for New GST Registrants (2026)

A significant development affecting new GST registrants is the mandatory adoption of InvoiceNow — Singapore’s nationwide e-invoicing network. From November 2025, all new voluntary GST registrants must use InvoiceNow-ready accounting or invoicing software. By April 2026, this requirement extends to all new GST registrants (compulsory and voluntary alike).

InvoiceNow enables businesses to send and receive invoices digitally in a structured data format (Peppol), reducing manual data entry and errors. Businesses that do not yet use InvoiceNow-ready software will need to upgrade their systems before applying for GST registration from April 2026 onwards. IRAS provides a list of InvoiceNow-ready solutions on its website.

What GST-Registered Businesses Must Do

Once registered, your business takes on the following ongoing obligations:

  • Charge and collect GST: You must charge GST (at 9%) on all standard-rated supplies and issue tax invoices to your GST-registered customers.
  • File quarterly GST returns (Form GST F5): GST returns must be filed with IRAS within one month after the end of each accounting period. Late filing attracts penalties.
  • Pay net GST to IRAS: If your output tax exceeds your input tax, you remit the difference to IRAS. If input tax exceeds output tax (a refund situation), IRAS will repay the excess.
  • Keep records for 5 years: All GST records — invoices, receipts, import documents — must be retained for at least 5 years.
  • Notify IRAS of changes: Any change to your business’s circumstances that may affect GST (such as a change of address, business structure, or the cessation of taxable activity) must be promptly notified to IRAS.

How to Apply for GST Registration

GST registration applications are submitted electronically via myTax Portal on the IRAS website using Corppass. You will need to provide details about your business, its taxable turnover, the basis for registration (compulsory or voluntary), and bank account details for any future GST refunds.

Processing typically takes 2 to 4 weeks. Once registered, IRAS will issue you a GST registration certificate with your unique GST registration number, which must appear on all tax invoices you issue. It is also important to ensure your company’s statutory records are in order — including your incorporation documents and ongoing compliance obligations — when applying for GST registration.

GST and Corporate Tax: Understanding the Difference

A common source of confusion for new business owners is the relationship between GST and corporate income tax. These are two entirely separate taxes:

  • Corporate income tax is levied on the company’s taxable profits (chargeable income) and is administered through IRAS’s annual corporate tax filing process (Form C-S or Form C).
  • GST is a transaction-based consumption tax levied on the value of goods and services supplied, filed quarterly through Form GST F5.

Both taxes require separate registrations, separate filings, and separate compliance processes. Many growing Singapore businesses find it helpful to engage an accounting firm to manage both their GST and corporate tax obligations together. Your company secretary can also help coordinate the administrative side of these filings.

Conclusion

GST registration is a significant milestone for any growing Singapore business. Whether you are approaching the compulsory S$1 million threshold or considering voluntary registration to recover input tax on business expenses, understanding the rules and obligations is essential before making a decision. With InvoiceNow requirements now in force for new registrants, planning ahead has never been more important.

If you need help determining whether your business should register for GST, managing GST compliance, or handling the broader range of corporate secretarial and tax obligations your Singapore company faces, the team at Raffles Corporate Services is here to assist. We support businesses at every stage — from incorporation through to full compliance — ensuring that your company remains in good standing with ACRA, IRAS, and MOM. Reach out to us today for a consultation.

— The Editorial Team, Raffles Corporate Services