Does GST InvoiceNow Cover Purchases? What Singapore Businesses Must Submit for Supplier Invoices

TL;DR

• GST InvoiceNow covers purchases, not just sales. IRAS wants invoice data for your standard-rated and zero-rated purchases too, including supplier credit notes.

• The buyer submits it. Even if your supplier already sent their copy to IRAS, you still submit yours, because it backs up your input tax claim.

• A PDF or paper bill can't be converted for you. Access Point Providers can't turn a PDF into Peppol data. Someone has to record it in an InvoiceNow-Ready Solution first.

• Deadline: purchase data must reach IRAS by the date you file the GST return, or its due date if that's earlier.

• What to do now: get your suppliers sending through InvoiceNow, tidy up petty cash, and pick software that receives Peppol invoices straight into your books. Checklist below.

Accurate as of 25 September 2026. Rules and dates come from IRAS and IMDA. Check the linked sources before you act.

The letter everyone reads the wrong way

Since mid-2026, IRAS has been telling GST-registered businesses their mandatory InvoiceNow implementation date. If yours arrived, you probably did what most owners do. You thought about your sales invoices.

The ones you send out are fine, you told yourself. The software can handle it. Maybe you'll need a Peppol ID. Job done.

Now picture the other side of your office.

The tray of supplier bills by the printer. The WhatsApp photos of delivery orders. The PDF invoices in someone's inbox with names like scan_0042.pdf. The petty cash envelope. The staff claim spreadsheet. The one supplier who still hands over a carbonless paper invoice.

That pile is part of GST InvoiceNow too. Almost nobody talks about it.

I've spent a lot of time with Singapore SMEs on dated software and spreadsheets. The sales side worries them because it faces customers. The purchase side is where the real hours go, and it's where the new requirement lands hardest. This article is about that pile: what IRAS asks for, why, and how to make it stop being a manual job.

What IRAS actually asks for: sales and purchases

The GST InvoiceNow Requirement says businesses must submit invoice data for transactions reported in the GST return. IRAS lists three groups:

• Standard-rated supplies and purchases

• Zero-rated supplies and purchases

• Exempt supplies

It covers any document that works as a bill, or adjusts one. IRAS names sales invoices, tax invoices, simplified tax invoices, serially numbered receipts, debit notes and credit notes.

Some things are left out. You don't submit data for reverse charge transactions, import permits, deemed supplies, goods exported without a sale, or exempt financial services.

"But my supplier already sent it to IRAS"

This is the most common pushback, and IRAS answers it directly in its FAQ (Q2.1). Your purchase data backs up the purchases and input tax you claim in your GST return. It's no different from today, when you already report standard-rated and zero-rated purchases in your GST F5.

Put simply: your supplier's copy proves they charged you GST. Your copy proves you're entitled to claim it back. IRAS wants both halves of the handshake.

That's why the purchase side matters so much. If your purchase data is late, messy or missing, it isn't just a filing problem. It sits right next to the money you're claiming back.

Two routes a supplier bill can take to IRAS

Every purchase invoice reaches IRAS one of two ways. Which one depends on how your supplier sends it.

Route 1: the supplier sends it through InvoiceNow. The bill arrives as structured Peppol data, straight into your accounting system. Nobody types anything. Once you post it, your InvoiceNow-Ready Solution can submit the purchase data to IRAS.

Route 2: the supplier sends a PDF, a photo or paper. IRAS is clear on this (FAQ Q3.2): Access Point Providers cannot convert PDF or paper invoices into Peppol format. You have to record the invoice data in an InvoiceNow-Ready Solution and submit it from there. IRAS calls this the solution-extracted submission method.

Here's the part that stings. Route 2 was always manual. Under GST InvoiceNow it's still manual, but now it must be done properly, in the right system, before your GST return is filed.

If most of your suppliers are on Route 2, you haven't avoided work. You've just moved it to the week before your GST filing deadline.

Everyday purchase scenarios, and what IRAS says

Real purchasing is messier than one supplier and one invoice. Here's how the common cases work, based on the IRAS page and FAQ.

That wrongful-GST row deserves a second look. IRAS has published a guide on validation checks that software can build in. In a manual process, a bad GST number on a supplier bill is easy to miss. You may only find out when the input tax claim is questioned.

The deadline, and the hours behind it

IRAS wants invoice data submitted by the earlier of two dates: the day you file the relevant GST return, or that return's filing due date. The "relevant" return is the one covering the period when the transaction happened.

For purchases, the transaction date is either the supplier's invoice date or, if you claim input tax on a posting basis, the date you posted the bill into your system. Either way, every purchase in the quarter must be in and submitted before you file.

Now some rough maths. These numbers are illustrative, not from IRAS, so swap in your own.

That's about three working days every quarter, for one person, just re-typing data that already exists in your supplier's system. Then add the time spent chasing a missing bill, fixing a typo in a GST amount, or working out why the input tax doesn't match the ledger.

Every supplier you move from Route 2 to Route 1 takes a slice out of that number, permanently.

The Supplier Bill Readiness Checklist

Use this to see how ready your purchase side is. Feel free to share it with your finance team or accountant. Score one point for each "yes".

1. We know our implementation date. We've checked the IRAS letter or the implementation date calculator.

2. We have a Peppol ID. Our business is registered in the SG Peppol Directory under our UEN, so suppliers can send to us.

3. Our software is on IMDA's list. It appears on the accredited InvoiceNow-Ready Solutions list, and it can receive e-invoices, not just send them.

4. We know our top 20 suppliers. We've listed them by number of bills a year, so we know where the manual work sits.

5. We've asked those suppliers to send via InvoiceNow. Each one has our Peppol ID and knows we prefer e-invoices.

6. All bills land in one place. Supplier bills go to one inbox or system, not to whoever the salesperson happened to email.

7. Petty cash and claims are batched. Staff claims and corporate card spend are captured regularly, ready to submit in batches.

8. We check supplier GST numbers. Our software or process flags a GST charge from a supplier who isn't GST-registered.

9. Bills are matched before payment. We tie supplier invoices back to purchase orders and goods received, so wrong amounts are caught early.

10. Purchases are closed before filing. We have a routine to post and submit all purchase data before the GST return goes in.

8 to 10: you're in good shape. Go to your suppliers and move more of them to Route 1.

4 to 7: the basics are there, but the manual pile will grow. Start with items 3, 5 and 6.

0 to 3: don't wait for your implementation date. IRAS notes that onboarding can take as little as 3 months, and most businesses complete their setup within a year.

When it applies to you, and the help available

IRAS is rolling the requirement out in phases. For businesses already registered, the phase depends on total annual supplies (Box 4 of the GST return) across the accounting periods ending in calendar year 2025.

Source: IRAS. For a plain-English walkthrough of how the timeline works, see our earlier piece, What Is InvoiceNow in Singapore?

Grants. IRAS lists a GST InvoiceNow Transition Grant of S$1,000 for SMEs with annual supplies up to S$4 million, and S$5,000 for larger businesses. Check eligibility on IMDA's InvoiceNow Grants page.

Free options. Free-of-charge solution packages are available up to 31 March 2031, with the current list of packages valid until 31 March 2027. They cover basic e-invoicing for compliance.

A word of honesty here: "basic compliance" and "no more manual purchase entry" are not the same thing. When you compare options, ask whether the tool can receive supplier e-invoices and post them to your books, or whether it only sends.

Frequently asked questions

1. Does GST InvoiceNow apply to purchase invoices?
   Yes. IRAS requires invoice data for standard-rated and zero-rated purchases, as well as supplies. Credit and debit notes are included.

2. My supplier isn't on InvoiceNow. Am I off the hook?
   No. You still submit the purchase data. You record the bill in an InvoiceNow-Ready Solution and submit it from there (IRAS FAQ Q3.2 and Q3.14).

3. Can my Access Point Provider convert our PDF bills for us?
   No. IRAS states that Access Point Providers can't convert PDF or paper invoices into Peppol format.

4. Do I have to submit every petty cash receipt one by one?
   No. IRAS allows petty cash purchases, staff claims and corporate card purchases to be aggregated before submission (FAQ Q3.4).

5. When is purchase data due?
   By the date you file the relevant GST return, or its filing due date, whichever is earlier.

6. Can suppliers still send us PDF invoices?
   Yes. A supplier can still issue PDF or paper copies. If you get both a Peppol invoice and a PDF of the same bill, make sure you don't claim the input tax twice (FAQ Q3.11).

7. What happens if we don't comply?
   IRAS says enforcement action may be taken against non-compliant businesses once their implementation date has passed (FAQ Q9.2).

Stop re-typing supplier bills with AveriWorks

We built AveriWorks for the people who handle that tray of supplier bills. It's on IMDA's list of free-of-charge InvoiceNow packages for GST-registered businesses, and it's built by Zetta Solution, an IMDA-accredited InvoiceNow-Ready Solution Provider and Access Point Provider. It's an ERP built for both InvoiceNow and GST InvoiceNow, so the purchase side is built in, not bolted on.

• InvoiceNow Inbox. Supplier e-invoices arrive as data and can post to your books automatically. No downloading, no re-typing.

• Purchase-to-pay in one place. Purchase orders, goods received notes and supplier invoices link up for three-way matching, so wrong amounts are caught before you pay.

• GST F5 straight from the ledger. Prepare your return from the same data you submitted, with GST submission and reconciliation reports included.

• Ask your data questions. The built-in AI answers questions like "how much did we spend with our top five suppliers last quarter?" in plain English.

There's a free tier that includes InvoiceNow, the InvoiceNow Inbox, supplier invoices and GST InvoiceNow, so you can get your Peppol ID and start receiving e-invoices without a budget meeting. When you need purchase orders, goods received notes and more users, the paid plans are on the pricing page.

Create your free AveriWorks account and make this the last GST quarter you spend re-typing bills.

Sources

Accurate as of 25 September 2026. Dates, grant amounts and rules can change, so always check the source.

1. IRAS, GST InvoiceNow Requirement: phases, scope of invoice data, deadlines, grants, free packages.

2. IRAS, Frequently Asked Questions for GST InvoiceNow Requirement (version dated 23 Sep 2026): Q2.1, Q3.2, Q3.4, Q3.11, Q3.14, Q4.1, Q4.6, Q6.4, Q9.2.

3. IRAS, e-Tax Guide: Adopting GST InvoiceNow Requirement for GST-registered Businesses.

4. IRAS, Recommended Features: Validation Check on Wrongful GST Charges.

5. IRAS, GST InvoiceNow Implementation Date Calculator (XLSX).

6. IMDA, InvoiceNow and InvoiceNow Grants.

7. IMDA, Accredited InvoiceNow-Ready Solution Providers and Free-of-charge solution packages (PDFs).

8. SG Peppol Directory.