InvoiceNow First-Quarter Reconciliation: A Singapore SME Guide for July 2026

If your business adopted InvoiceNow during the previous quarter, reconciling for the first time means doing three checks in sequence: confirm every e-invoice you transmitted matches a sales entry in your ledger, confirm every e-invoice you received matches a recorded purchase, and confirm that both sets agree with the output and input tax you are about to declare on your GST F5. The reason this first quarter feels different is that InvoiceNow routes invoices through the Peppol network rather than email or PDF, so your accounting system, your access point, and IRAS now each hold a version of the truth — and your job is to prove they are the same version before you file.

Why is the first quarter on InvoiceNow harder than later ones?

The first reporting period after go-live is where structural gaps surface. During the changeover, most SMEs run a hybrid: some customers received Peppol e-invoices, others were still on PDF, and a handful of credit notes or recurring invoices were issued in the old system before the cut-over date. That mix is normal, but it means your transaction count in the accounting ledger will rarely match the count in your access point dashboard on the first try.

The other complication is direction. InvoiceNow handles both outbound (what you bill) and inbound (what suppliers bill you). Outbound errors inflate or understate your output tax; inbound errors affect the input tax you claim. A clean reconciliation has to walk both directions separately, because a single net figure can hide an offsetting pair of mistakes.

What should you reconcile first — sales or purchases?

Start with outbound sales, because that is the data you control end to end. Pull a list of every e-invoice your access point successfully transmitted during the quarter, then match it line by line against the sales invoices posted in your accounting system. You are looking for three failure modes: an invoice that was posted but never transmitted (it sat in a draft or failed validation), an invoice that was transmitted but not posted (a duplicate or a manual entry that bypassed the system), and amount mismatches where the GST line on the e-invoice differs from the ledger.

Once sales tie out, move to inbound. List the e-invoices you received through the network and match them to recorded supplier bills. The common gap here is a received e-invoice that was never entered as a payable — which means you would miss a legitimate input tax claim. Flag any supplier still sending PDFs so you can decide whether to onboard them or keep handling them manually.

How do you tie the e-invoice data back to your GST F5?

Your GST F5 declares output tax (Box 6), input tax (Box 7), and the value of standard-rated supplies and purchases. After your sales and purchase reconciliations are clean, the totals should roll up directly into those boxes. Build a one-page bridge: ledger output tax, plus or minus any timing items (invoices dated in the period but transmitted after the cut-off), equals the figure in Box 6. Do the same for input tax into Box 7.

Pay attention to three items that routinely break this bridge:

• Credit notes: a credit note issued over InvoiceNow must reduce output tax in the same period. If it was raised in the old system, confirm it landed in the ledger.
• Foreign-currency invoices: the exchange rate on the e-invoice and the rate your accounting system applied must agree, or the GST value will drift.
• Zero-rated and exempt supplies: these still pass through InvoiceNow but carry no output tax — make sure they are classified correctly so they do not inflate Box 6.

What records should you keep for IRAS?

Keep the transmission and delivery confirmations from your access point alongside the accounting entries they correspond to. The value of e-invoicing is the audit trail: each invoice carries a delivery status, so for the first quarter, export that status report and file it with your GST working papers. If IRAS later queries a transaction, you want to show not just that you raised the invoice but that it was delivered through the network and posted to the correct period. Retention rules are unchanged — five years — but the format is now digital, so confirm your backups capture the structured data, not only a rendered PDF copy.

How do you stop this becoming a quarterly fire drill?

The fix is to make reconciliation continuous rather than a quarter-end scramble. Set a weekly fifteen-minute check that compares transmitted invoices against posted sales while the volume is small and the details are fresh. Use your accounting software's bank feed and Peppol integration together so that received e-invoices auto-populate as draft bills, leaving you to approve rather than re-key. For lean teams, this is exactly the kind of repetitive matching that a well-configured automation — or a managed service — can own, freeing your one finance person to investigate the genuine exceptions instead of all of them.

Treat this first reconciliation as the moment you set the standard. Document the steps that worked, note the suppliers and invoice types that caused friction, and the second quarter will take a fraction of the time.

Frequently Asked Questions

Do I still file a GST F5 the same way after adopting InvoiceNow?
Yes. InvoiceNow changes how invoices are transmitted and how their data flows into your records, but you still file the F5 through myTax Portal as before. The benefit is that clean e-invoice data makes the boxes faster to populate and easier to defend in a query.

What if some of my customers or suppliers are not on InvoiceNow yet?
That is expected during the transition. Keep handling those parties through your existing process and reconcile them manually, but flag them so you can onboard the high-volume ones. A mixed environment is fine as long as every invoice — Peppol or PDF — ends up posted to the correct GST period.

My e-invoice total does not match my ledger. Where do I start?
Split the difference by direction first: reconcile sales separately from purchases. Most first-quarter mismatches come from invoices posted but not transmitted, or received but not entered as payables. Check those two categories before assuming a tax-rate error.