Unfiscalised invoices before a Nigerian VAT return
How a Nigerian business finds invoices, credit notes and till sales that were never fiscalised, and clears them before its VAT return is due.
By Achekam · · 5 min read · For Running a business businesses in Nigeria
Launching soon. Some of the screens this article describes for Nigerian and Kenyan businesses are not reachable in Achekam yet. They are coming soon.
Under Nigeria's e-invoicing system, an invoice is not finished when the customer receives it. It is finished when it has passed through the Nigeria Revenue Service's Merchant Buyer Solution and come back with an Invoice Reference Number, the IRN. Until then it is "not fiscalised", and the law treats that as a failure in its own right.
In a busy month, some documents slip through: a credit note raised in a hurry, an invoice issued while the provider's connection was down, a batch of till sales from a weekend event. The VAT return is the natural moment to catch them, because it is where every taxable document for the month comes together. This article explains how to use it that way.
What the VAT return lists
When Achekam prepares a Nigerian VAT return for a period, it also lists the period's invoices, credit notes and till sales that have not been fiscalised. Think of it as an exceptions report attached to the return: everything on it is a document that, as far as Achekam's records show, never received its IRN.
There is one case where the list does not apply. If your accountant prepares your return from sales and purchase schedules they imported, rather than from your own books in Achekam, there are no documents to check, and the list is marked as not applicable. In that case, run the same check against your own invoicing records.
Why it warns but does not block
Achekam lists the unfiscalised items but does not stop the return. That is deliberate. Your VAT is due on your supplies whether or not each invoice was fiscalised, so refusing to prepare the return would only push you towards a late filing on top of the e-invoicing problem.
The warning is still a warning. A return prepared with items on the list means two obligations are out of step: you are declaring the VAT, but the NRS has not seen those invoices through its e-invoicing system. Treat every line on the list as a task to clear, not as a note to read.
What a document says until it is fiscalised
Achekam prints the MBS identifiers on an invoice only once that invoice has been fiscalised. Before that, the document says plainly that it is not yet fiscalised. A test submission made in a sandbox is labelled as test only, so a practice run can never pass for the real thing.
This matters for customers too. A buyer who receives an invoice marked "not yet fiscalised" may well ask for the fiscalised version. If a customer queries such an invoice, the answer is to fiscalise it and send the updated document, not to argue.
Clearing each item through your provider
Achekam is not an NRS-accredited Access Point Provider or System Integrator, and it never generates an IRN itself. Fiscalising goes through your own provider. Where Achekam has no working connection to that provider, each Nigerian e-invoice is held as manual pending, with a JSON or XML file ready for upload.
For each item on the list, the routine is:
- Download the invoice's e-invoice file from Achekam.
- Upload it through your Access Point Provider and wait for the response.
- Record the IRN the provider returns against the invoice in Achekam.
- Have a second person check the recorded IRN against the provider's response.
Only after that second check does the invoice count as fiscalised, and only then does it drop off the list. The second check is not red tape: a mistyped IRN would leave you believing an invoice is fiscalised when the NRS has no record of it under that number.
Credit notes and till sales go through the same steps. Till sales are easy to forget because no customer asks for them, so look at that part of the list first. The NRS describes what its e-invoicing system does, from creating and validating invoices to submitting and tracking them against your Tax ID, on its e-invoice portal page.
The cost of leaving an invoice unfiscalised
The penalty is set out in section 104 of the Nigeria Tax Administration Act 2025: failing to fiscalise an invoice costs ₦200,000, plus a sum equal to the full tax on it, plus interest. It is charged per invoice, so a month with many unfiscalised documents can cost far more than the VAT on them.
Set that beside the effort involved, which is one upload and one check per document. Clearing the list every month is plainly the cheaper course.
A check to run before the 21st
A Nigerian VAT return, including a nil return, is due on or before the 21st of the following month. Build the e-invoicing check into the days before it:
- First working day of the month. Prepare the VAT return for the month just ended and open the list of unfiscalised documents.
- Within the week. Upload each listed document through your provider and record its IRN.
- Before review. Ask the second person to verify every IRN recorded that week.
- Before filing. Prepare the return again and confirm the list is empty, or that each remaining item has a written reason, such as a provider fault you have reported.
- After filing. Note any document you could not clear and follow it up with your provider the same week.
A list that is empty before the 21st is the sign that your invoicing and your VAT agree. For the provider side, including how the upload file is produced and why you choose and contract the provider yourself, read e-invoicing through an Access Point Provider. The return itself, its due date and nil months are covered in Nigerian VAT returns: due dates and nil returns, and testing the connection safely before going live is explained in testing e-invoicing in the sandbox.
Open this month's list today, even if the return is weeks away. Every document cleared now is one less to chase on the 20th.
General guidance only, not advice on your own circumstances. Tax and payroll rules change: check the current position with the authority or your adviser.
