What's actually happening
InvoiceNow is Singapore's national e-invoicing network. It runs on Peppol, an open international standard, and IMDA introduced it back in 2019. It lets businesses send and receive invoices as structured data rather than as PDFs someone has to retype.
What's new is the GST layer. IRAS now requires GST-registered businesses to transmit invoice data directly to IRAS through that network, using an InvoiceNow-Ready solution. This is in addition to whatever invoicing arrangement you already have with your customers. You're not being told to change how you bill people.
Why now
It started small. Voluntary early adoption opened on 1 May 2025. From 1 Nov 2025 it became mandatory for newly incorporated companies registering for GST voluntarily, and from 1 Apr 2026 for all new voluntary registrants regardless of when they were incorporated or how they're structured.
Then the scope widened to everyone. All GST-registered businesses will be required to onboard, rolled out progressively from 1 Apr 2028 to 1 Apr 2031. That brings roughly 90,000 more businesses onto the network. IRAS has also been notifying businesses registered before 2026 of their individual implementation dates, so if a letter turned up recently, that's what it was.
The phase table
| Date | Who it applies to |
|---|---|
| 1 May 2025 | Voluntary early adopters (any existing GST-registered business) |
| 1 Nov 2025 | Companies registering for GST voluntarily within 6 months of incorporation |
| 1 Apr 2026 | All new voluntary registrants |
| 1 Apr 2028 | All new compulsory registrants, and existing registrants with total supplies of S$200,000 or less |
| 1 Apr 2029 | Existing registrants with total supplies up to S$1 million |
| 1 Apr 2030 | Existing registrants with total supplies up to S$4 million |
| 1 Apr 2031 | Existing registrants with total supplies above S$4 million |
Total supplies means Box 4 of your GST return (standard-rated, zero-rated and exempt supplies) across all accounting periods ending in 2025.
Working out GST on an amount while you're here? Use our free Singapore GST calculator.
What "InvoiceNow-Ready" actually means
Two things have to be true. Your invoicing system has to produce invoice data in the right structured format, and you have to be connected to the network through an accredited Access Point provider.
Most mainstream accounting software in Singapore either already qualifies or is working on it. If you're on Excel, Word templates, or a duplicate book, you don't have a system to make ready. That's the harder starting point, and the one worth starting on early.
What it changes day to day
Less retyping. Invoice data moves between systems instead of being read off a PDF and keyed in again, which cuts the reconciliation work and the transcription errors that come with it. Faster GST audits and refunds, since IRAS already has the data. And for businesses trading with government agencies or others already on the network, fewer chases for invoices that went missing in someone's inbox.
What to do before your date
If you're on accounting software. Ask your vendor whether you're InvoiceNow-Ready and what the connection step involves. This is often configuration rather than migration.
If you're on Excel or templates. Your work isn't the onboarding, it's the foundation: consistent customer records, correct GST codes, one source of truth for what you've billed. Sort that first; the software decision gets much easier afterwards.
Either way. Onboard before your deadline rather than on it. Early onboarding means you find your data problems when they're inconvenient instead of when they're urgent, and the transitional funding is there now.
Common questions
What is the GST InvoiceNow requirement?
It's an IRAS requirement for GST-registered businesses to transmit invoice data to IRAS electronically through the InvoiceNow network, using an InvoiceNow-Ready solution. It's on top of how you invoice your customers today.
Who does InvoiceNow apply to?
GST-registered businesses in Singapore, in phases. New voluntary registrants are already in scope; existing GST-registered businesses follow progressively based on their total 2025 supplies.
How do I find my InvoiceNow deadline?
It depends on how and when you registered for GST and your total supplies for accounting periods ending in 2025. This checker gives you a fast read, and if you've received an IRAS letter, the date in the letter applies.
Does InvoiceNow change how I send invoices to my customers?
No. It's about transmitting invoice data to IRAS in a structured format. It sits on top of however you bill your customers today.
Is there funding to help with onboarding?
IRAS lists free-of-charge solution packages with basic e-invoicing capability, and transitional funding is available to offset onboarding costs. Check the free list before buying anything.
Where to check
The definitive source is the IRAS GST InvoiceNow Requirement page, which includes the e-Tax Guide and an official implementation date calculator. That calculator is precise but takes 15 to 20 minutes and needs Excel 2021 or Excel Online, along with your GST registration date, filing frequency, accounting period cycle and Box 4 figures for every 2025 return. This tool is the 30-second version using a rough band. If your situation is unusual, use theirs or check with your accountant.