Singapore is moving its entire GST-registered business population onto e-invoicing. The GST InvoiceNow Requirement started quietly in November 2025 with newly incorporated voluntary registrants; the Committee of Supply 2026 announcement extended it to every GST-registered business by April 2031 [2] . If you keep books for Singapore companies, the next five years have a fixed schedule, and the right time to understand it is before IRAS’s notification letter lands. Every date and threshold below comes from IRAS sources listed in the Sources section.
What InvoiceNow actually is
InvoiceNow is the nationwide e-invoicing network introduced by the Infocomm Media Development Authority (IMDA) in 2019, built on the international Peppol standard [1] . Instead of a supplier emailing a PDF that someone retypes into the buyer’s accounting system, the invoice travels as structured data from one accounting system to another through accredited Access Point providers. Over 63,000 Singapore businesses are already on the network [2] .
The GST InvoiceNow Requirement adds a tax layer on top: GST-registered businesses must transmit their invoice data to IRAS through InvoiceNow-Ready Solutions, giving IRAS invoice-level visibility rather than only the summary totals in a GST return [1] . IRAS cites faster GST audits and refunds as the direct benefit to compliant businesses [2] .
The full phase-in timeline
| From | Who must comply |
|---|---|
| 1 November 2025 | Companies that register for GST voluntarily within 6 months of incorporation |
| 1 April 2026 | All voluntary GST registration applications on or after this date, any structure or incorporation date |
| 1 April 2028 | Compulsory GST registrations applied for on or after this date, plus existing GST businesses with annual supplies of S$200,000 or less |
| 1 April 2029 | Existing GST businesses with annual supplies of S$1 million or less |
| 1 April 2030 | Existing GST businesses with annual supplies of S$4 million or less |
| 1 April 2031 | Existing GST businesses with annual supplies above S$4 million |
“Total annual supplies” means the value of standard-rated, zero-rated, and exempt supplies (Box 4 of the GST return) across the prescribed accounting periods ending in calendar year 2025 [1] . Note the unusual direction: smaller businesses go first. IRAS’s reasoning is that small businesses mostly run on off-the-shelf accounting software that is already InvoiceNow-Ready, while larger businesses need time to fit the requirement into enterprise IT cycles [2] .
Businesses registered before 2026 do not need to work out their own date: IRAS is notifying each of them of their mandatory implementation date by mid-2026, and publishes an implementation date calculator in the meantime [1] .
Who is excluded
Two groups are outside the requirement entirely [1] :
- Overseas entities, including suppliers registered under the Overseas Vendor Registration (OVR) pay-only and full regimes.
- Businesses liable to register for GST wholly because of the Reverse Charge regime.
Everyone else who is GST-registered, including sole proprietors and partnerships once their phase arrives, is in scope.
Grants and free solutions
The Government attached money to the COS 2026 extension [2] :
- Transitional funding of up to S$1,000 for SMEs and up to S$5,000 for larger businesses, offsetting onboarding costs.
- Free InvoiceNow-Ready Solutions for SMEs until March 2031.
Onboarding early is cheaper than onboarding under deadline pressure, and IRAS explicitly encourages businesses to activate the transmission feature ahead of their mandatory date [1] .
What changes for the bookkeeper
The practical work splits into three steps:
- Check the software. If the client runs an InvoiceNow-Ready Solution (the major cloud platforms, including Xero, are accredited), compliance is an activation and registration exercise, not a migration. If they invoice from spreadsheets or Word templates, they need to move before their phase date.
- Register on the network through an accredited Access Point, and activate the GST InvoiceNow transmission feature so invoice data flows to IRAS.
- Keep the records straight across two channels. E-invoices arrive as structured data; everything else (expense receipts, overseas supplier invoices, petty cash) still arrives as paper and PDFs. Both end up in the same GST return.
That third point is where ExpenseFlow fits. InvoiceNow digitises the invoices exchanged between network members; it does nothing for the receipts your client’s team brings back from lunch, the subscription bills that arrive by email, or invoices from overseas suppliers who are excluded from the network. ExpenseFlow captures those documents, extracts and codes them with the correct GST treatment, and syncs them into Xero with the source document attached, so the ledger IRAS sees through InvoiceNow and the ledger built from unstructured paper stay one ledger. ExpenseFlow does not transmit data to IRAS; that is the accounting platform’s job.
References
Sources and references
Every figure, threshold, deadline, and regulatory rule cited in this guide is traceable to an official government publication. URLs are reproduced in full so any reader can verify the claim at source. Numbers are subject to change at each fiscal event; we re-check this list at every quarterly refresh of this guide.
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[1]
IRAS · GST InvoiceNow Requirement
https://www.iras.gov.sg/taxes/goods-services-tax-(gst)/gst-invoicenow-requirementPhase table, Box 4 supplies definition, exclusions, mid-2026 notifications.
Retrieved 2026-06-11
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[2]
IRAS · Committee of Supply 2026: Extension of GST InvoiceNow Requirement to All GST-registered Businesses by April 2031
https://www.iras.gov.sg/news-events/newsroom/committee-of-supply-2026--extension-of-gst-invoicenow-requirement-to-all-gst-registered-businesses-by-april-20312028-2031 schedule, transitional funding, free SME solutions, network statistics.
Retrieved 2026-06-11