GST InvoiceNow requirement: plan backwards from your IRAS date

A letter from IRAS naming a date in 2028 or 2030 is easy to file under “later”. For a small GST-registered business, it is really the deadline for a systems change: sending invoice data to IRAS through InvoiceNow, Singapore’s Peppol-based e-invoicing network.

Under the GST InvoiceNow Requirement, new voluntary GST registrants have been covered since 1 April 2026. Existing GST-registered businesses join in phases from 1 April 2028 to 1 April 2031, smallest first. IRAS has been notifying businesses registered before 2026 of their individual dates since mid-2026.

The useful work this autumn is finding your date, listing where every invoice comes from and choosing a route you can trial before it applies.

At a glance

• Already in force: newly incorporated companies registering voluntarily within six months of incorporation (from 1 November 2025) and all new voluntary registrants (from 1 April 2026).
• 1 April 2028: new compulsory registrants, and existing registrants with total annual supplies of $200,000 or less.
• 1 April 2029, 2030 and 2031: existing registrants with supplies of up to $1 million, up to $4 million and above $4 million respectively.
• How the phase is set: total standard-rated, zero-rated and exempt supplies in GST periods ending in calendar year 2025.
• Support announced: transitional funding of up to $1,000 for SMEs (up to $5,000 for larger businesses) and free InvoiceNow-Ready Solutions for SMEs until March 2031, in IRAS’s Committee of Supply 2026 announcement.
• Next step: check the date in IRAS’s notification, or use IRAS’s implementation date calculator.

What changes for a small business?

Under the requirement, invoice data for transactions reported in the GST return goes to IRAS through an InvoiceNow-Ready Solution. IRAS’s guidance covers documents that bill for, or adjust bills for, supplies and purchases: tax invoices, simplified tax invoices, serially numbered receipts, and debit and credit notes.

IRAS’s e-Tax Guide allows point-of-sale, simplified tax invoice and petty cash data to be aggregated before submission. Overseas entities, including vendors under the Overseas Vendor Registration regime, are exempt, as are businesses registered only because of reverse charge.

Worked example: a print shop maps its paperwork

Consider a fictional six-person print and signage shop in Kallang, GST-registered since 2019. Its GST periods ending in 2025 show total supplies of about $780,000, which on IRAS’s thresholds points to the 1 April 2029 phase. The date in IRAS’s notification is still the one it plans against.

The office manager lists every document that touches the GST return, and where it starts:

• Tax invoices to corporate clients: the accounting software.
• Walk-in sales: a point-of-sale terminal.
• Credit notes for reprints: a spreadsheet template.
• Supplier invoices for paper and ink: email attachments.
• Petty cash purchases: paper receipts in an envelope.

The software may already handle invoices, but the spreadsheet credit notes, counter sales and emailed supplier bills each need a decision. The owner plans questions to both providers before the end of 2026, a choice of route in 2027 and a trial over a full GST quarter in 2028. The shop, its figures and its dates are invented.

Which route fits your business?

Most small firms start from one of three positions:

1. Your accounting software is already InvoiceNow-Ready. Ask the provider in writing which of your document types it sends, then trial it with real transactions.
2. You invoice from spreadsheets, templates or receipt books. Choose an InvoiceNow-Ready Solution, and check what the free SME offer includes before relying on it.
3. You run your own system or ERP. Expect an integration project to connect it to an Access Point provider, a route described on IMDA’s InvoiceNow grants page. Allow the most time for this route.

Treat point-of-sale systems separately: they often come from another vendor, yet their data must still match your return.

A readiness checklist for this quarter

1. Record the date in IRAS’s notification, and who received it.
2. List every document that feeds the GST return, and where it is created or received.
3. Mark those your current systems cannot yet send or receive through InvoiceNow.
4. Ask each provider whether its product is InvoiceNow-Ready, and for which document types.
5. Clean customer and supplier records: legal names, UENs and GST registration numbers.
6. Name an owner, and decide who corrects mistakes through credit or debit notes.
7. Trial the route for at least one full GST period before your date, reconciling the data with your return.
8. Recheck funding terms and provider pricing before you commit.

Then write the invoice-handling steps down, awkward cases included; our guide to documenting a process shows how.

Should you adopt before your date?

IRAS is encouraging it, citing faster GST audits, quicker refunds and built-in checks against being wrongly charged GST; those are its stated aims, not outcomes we can predict. Opening the first InvoiceNow Fair on 29 July 2026, Deputy Commissioner Dennis Lui urged businesses to get on board early rather than wait for their mandate, noting that hundreds of businesses, mostly larger ones, had begun submitting invoice data by June.

Early adoption suits a business whose software is already InvoiceNow-Ready, or one changing systems at the start of a financial year anyway. It may not suit a shop in its busiest season. The time-saving calculator can put rough numbers on switching early; treat the result as an estimate.

Common questions