You look at a recent invoice and see, at the bottom, a QR square and a code starting with “ATCUD:”. They’re not decorations or optional - they’re required by law (the ATCUD on every invoice; the QR code on those issued by certified software) and they help identify and trace each invoice (and let your client register it on e-Fatura). Here’s what they are and what you have to do.
What they are
They’re part of the same legal package (Decree-Law 28/2019 and Ordinance 195/2020), created to fight fake invoices and the shadow economy:
In practice, where there’s a QR code the ATCUD appears above it. The ATCUD must be on every page of the document; the QR code is required on documents issued by certified software.
Where the ATCUD comes from
Here’s the one part that needs an action from you: the validation code that forms the ATCUD isn’t made up - it’s assigned by the AT when you communicate your document series. After that, each invoice in that series carries the ATCUD automatically.
How you do it depends on how you invoice:
- The Portal handles communicating the series
- The ATCUD comes out on the invoice (the QR is certified-software only)
- Nothing to install
- The program usually communicates the series to the AT for you (check the setup)
- It generates the ATCUD and QR automatically
- It must be AT-certified software
So if you use the Portal das Finanças or a certified program, this happens automatically, as a rule - you don’t have to calculate anything (but confirm the series was communicated). There are also documents pre-printed by an authorised printer; the mistake to avoid is invoicing outside the lawful channels - a hand-made Word document, say, which isn’t a valid document.
Careful: the ATCUD depends on your series being communicated to the AT. If you switch software, or open a new series, confirm the communication was done - otherwise invoices come out without a valid code. When in doubt, your accountant or the software’s support confirms it in a minute.
✅ In summary
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The ATCUD and QR code are mandatory on invoices (ATCUD since 2023, on all documents; QR since 2022, on certified-software ones) - part of the fight against fake invoices (DL 28/2019 + Ordinance 195/2020).
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The ATCUD comes from the series communicated to the AT. If you invoice on the Portal das Finanças or in certified software, the ATCUD comes out automatically - you just need the series to be communicated. The QR code appears only on certified-software invoices (the Portal and pre-printed documents don’t generate it).
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With FIZ your invoices come out with the ATCUD and QR code already on them, compliant, without you having to think about it. See the plans.
