GST registration, filing and InvoiceNow — Complete 2026 guide

GST registration, filing and InvoiceNow together make up a Singapore business’s goods and services tax obligations. This 2026 guide explains when GST registration is compulsory, how returns are filed, and how the InvoiceNow e-invoicing requirement affects newly registered businesses, so GST registration, filing and InvoiceNow are managed correctly.

Raffles Corporate Services works with a panel of corporate and employment law firms; this article is general information, not legal advice.

What GST registration, filing and InvoiceNow mean

Goods and Services Tax (GST) is Singapore’s broad-based consumption tax, charged at 9% from 1 January 2024. A GST-registered business charges GST on its taxable supplies (output tax), claims GST on its purchases (input tax), and accounts for the difference to IRAS through periodic returns. InvoiceNow is the nationwide e-invoicing network based on the international Peppol standard, which IRAS is progressively requiring GST-registered businesses to adopt for transmitting invoice data.

Who must register for GST

Registration is either compulsory or voluntary:

  • Retrospective test: taxable turnover exceeded S$1,000,000 at the end of the calendar year.
  • Prospective test: taxable turnover is reasonably expected to exceed S$1,000,000 in the next 12 months.
  • Voluntary registration: available to businesses below the threshold that wish to claim input tax, subject to conditions.

Our companion guide on when a Singapore company must register for GST works through the tests with examples.

Cost, timeline and the GST calendar

Key figures for 2026:

  • GST rate: 9%.
  • Registration threshold: S$1,000,000 taxable turnover.
  • Registration deadline: apply within 30 days of becoming liable under the retrospective or prospective test.
  • Return frequency: typically quarterly, with the GST F5 due within 1 month after the end of each accounting period.
  • Late filing: a late submission penalty applies, and a 5% penalty applies to tax paid late.

InvoiceNow: the e-invoicing requirement

IRAS is phasing in a requirement for GST-registered businesses to transmit invoice data to IRAS via the InvoiceNow network. The roll-out began with newly incorporated companies that register for GST voluntarily and extends progressively to other GST-registered businesses. Adopting InvoiceNow means connecting an accounting or e-invoicing solution to the Peppol network so that structured invoice data flows to counterparties and to IRAS automatically.

Step-by-step: registering and filing GST

  1. Monitor taxable turnover against the S$1,000,000 threshold on both the retrospective and prospective tests.
  2. Apply for registration through the IRAS myTax Portal within 30 days of becoming liable.
  3. Once registered, charge 9% GST on taxable supplies and issue compliant tax invoices.
  4. Connect an InvoiceNow-ready solution where the e-invoicing requirement applies.
  5. File the GST F5 return for each accounting period and pay any net GST within 1 month of period-end.
  6. Keep tax invoices and records for at least 5 years.

Statutory basis

GST is imposed under the Goods and Services Tax Act 1993. Section 9 of the Goods and Services Tax Act 1993 addresses the liability to be registered, and the First Schedule sets the registration thresholds. Section 41 of the Goods and Services Tax Act 1993 deals with the filing of returns and payment of tax. Compliance is therefore a statutory obligation backed by penalties for default.

Common mistakes and gotchas

Frequent issues include monitoring only the retrospective test and missing the forward-looking prospective test, late registration, claiming input tax on blocked expenses such as private motor car costs, and failing to issue compliant tax invoices. Businesses moving onto InvoiceNow sometimes underestimate the lead time to connect their accounting system to the network.

Authoritative sources

See IRAS GST and InvoiceNow guidance at iras.gov.sg, accounting standards set by the Accounting Standards Committee, and company filing requirements from ACRA.

Frequently asked questions

What is the GST registration threshold in 2026?
Compulsory registration is triggered when taxable turnover exceeds S$1,000,000 under either the retrospective or prospective test.

What is the current GST rate?
9%, effective from 1 January 2024.

Is InvoiceNow mandatory for all businesses?
It is being phased in. The requirement began with newly incorporated companies registering for GST voluntarily and is extending progressively to other GST-registered businesses.

How often are GST returns filed?
Most businesses file quarterly, with the GST F5 due within one month after the end of each accounting period.

Related guides

For wider context, see our the foreign-sourced income exemption, our Employment Pass and S Pass salary thresholds, and when a Singapore company must register for GST.

Need help with this? Call, SMS or WhatsApp +65 8501 7133, or email [email protected]. Raffles Corporate Services works with a panel of corporate and employment law firms; this article is general information, not legal advice.