How to correct VAT fields and check against the AT

What is it for?

A periodic VAT return with an amount in the wrong field, or without the adjustment for a credit note, has to be corrected before it is submitted. fiscaldoo offers three ways, all for the period still open: notes with an adjustment reason (they feed fields 40 and 41 and the annexes), correcting the field of a line already posted (adjustment entry) and checking the amounts against those the AT shows (typed in by hand). A return already submitted cannot be changed: it is corrected with a replacement return.

Pending validation by a certified accountant: VAT Code (CIVA) art. 78 and where each reason goes in fields 40 and 41 (the table is product data, with its own sources); deadlines for each reason; when a correction requires a replacement return instead of an adjustment.

When to use it?

• You issued or received a credit or debit note that changes the VAT, and the amount has to go to field 40 or 41.
• A VAT amount went to the wrong field of the return because of the tag on a posted line.
• You want to check the return against the amounts the AT shows pre-filled on the Portal before validating it.

Pending validation by a certified accountant: correspondence of the fields mentioned with the official table of the periodic VAT return, in the situations where the correction is used.

Where to find it?

• Reasons and returns: Accounting › Declare › VAT › What is there to do with the VAT?; in the VAT configuration group, VAT adjustment reasons; in the Supporting lists group, VAT return records.
• Note with a reason: Accounting › Record › Supplier credit notes (or customer credit notes), VAT regularization reason field.
• Field correction: on a posted invoice, Journal items tab, tag icon next to the account of the VAT line.

Before you start

• Fiscal officer profile (with Certified Accountant / Fiscal Manager) for all steps. Correcting a line's field really does require the Fiscal officer; editing and checking the return requires Fiscal administration or Fiscal officer. The Accountant does not see the configuration tables.
• The period's return is in Draft or Computed.
• Know which art. 78 rule applies. The table has 10 reasons, for example 78.º n.º 2 (cancellation or reduction of the operation; field 40), 78.º n.º 4 (the acquirer corrects the deduction; field 41), 78.º n.º 6 (material or calculation errors, in favour of the taxable person or of the State) and e-Taxfree.

Pending validation by a certified accountant: correspondence of the fields mentioned with the official table of the periodic VAT return, in the prerequisites for the correction.

How to use it

1. Credit note with an adjustment reason

1. Issue the note from the invoice (Reverse, or Supplier credit notes). If you try to Confirm without a reason, the screen refuses: “O documento … altera o valor tributável ou o IVA, por isso vai ao campo 40 ou 41 da declaração periódica e precisa de um motivo de regularização de IVA. O art. 78.º do CIVA exige um motivo de uma lista fechada: escolha o motivo … no campo “Motivo da regularização de IVA” do documento e publique-o de novo.” (the document changes the taxable amount or the VAT, so it goes to field 40 or 41 of the periodic return and needs a VAT adjustment reason; CIVA art. 78 requires a reason from a closed list: choose it in the document's VAT regularization reason field and post it again)
2. In VAT regularization reason, choose the reason. Regularization reference date (pre-filled with the original invoice date: 28/10/2026) and Regularization proof, which some reasons require, appear.
3. Confirm the note. In the example, RFTF/2026/00001, purchase credit note for FTF/2026/00048 (diesel, €100.00 + €23.00), with reason 78.º n.º 4.

The note generates the reverse entry of the invoice:

Account	Debit	Credit
2211 Fornecedores gerais	€123.00
6242 Combustíveis (reverses the expense)	€0.00	€100.00
6242 Combustíveis (splits the expense)	€50.00
6242 Combustíveis (“base of the expense (VAT partly deductible)”)		€50.00
6242 Combustíveis (“non-deductible VAT (CIVA art. 21.º)”)		€11.50
2432 IVA - Dedutível		€11.50

Pending validation by a certified accountant: correspondence of the fields mentioned with the official table of the periodic VAT return, in this adjustment by credit note.

2. Annexes 40 and 41 and fields 40 and 41

1. Open VAT return records and the period's return (2026 / 11). Click Calculate.
2. On the Annexes 40 and 41 tab, click Pre-fill from the regularization notes. The note's line appears in the Annex of field 41 (in favour of the State), with Reason (art. 78.º) “Acquirer corrects the deduction after the supplier cancelled, reduced or rectified”, Origin date 28/10/2026 and VAT regularized €11.50. The Annex 41 total is €11.50.
3. On the Quadro 06 — fields tab, field 41 shows €11.50 and field 40 is at zero.

The line's Taxable amount shows €150.00, not the €100.00 of the note: do not use that amount without checking it against the document. Annex lines can be edited by hand; the edit is recorded in Manual edits.

Pending validation by a certified accountant: correspondence of the fields mentioned with the official table of the periodic VAT return, in annexes 40 and 41 and fields 40 and 41.

3. Correct the field of a line already posted

1. Open the posted invoice (Fiscal officer), Journal items tab, and click the tag icon on the 2432 IVA - Dedutível line. Correct declaration field (tag) opens: “The posted entry is not changed. A new adjustment entry is created: it takes the amount out of the wrong declaration field and puts it in the correct one, with no effect on the accounts.”
2. Choose the Wrong tag and the Correct tag (different), the Correction date and write the Reason. Click Create adjustment entry.
3. Calculate the period's return again.

The adjustment (OD/2026/00106, posted on 01/11/2026) has two lines on 2432 IVA - Dedutível, of €23.00: a credit with the wrong tag and a debit with the correct one. The account balances do not change. The original invoice stays intact and is linked to the adjustment through the Tag corrections button. The tags appear with their technical name (for example trp_tax_favor_company_22), not with the field number: ask the certified accountant for the correspondence table.

4. Check against the amounts the AT shows

This check is manual: fiscaldoo never contacts the AT. Open the Portal das Finanças outside fiscaldoo and copy the amounts.

1. On the return, Tax Authority values tab, click Add a line. Enter the Field, the Type (Basis or Tax) and the Tax Authority value. Example on the October return: field 4, Tax, €40.00; field 24, Tax, €34.50; field 7, Basis, €100.00.
2. Click Compare with the system. Each line shows the Tax Authority value, the System value and the Difference: field 4 differs (€46.00 in the system, difference −€6.00), field 24 matches (€34.50), field 7 does not exist in the system (€100.00 difference).
3. Open the Divergences with the Tax Authority list and fix the cause in the accounts (or confirm that the AT's figures are out of date). Calculate again.

The AT's amounts never go into the return: they are only for checking. They can only be recorded while the return has not been submitted.

Pending validation by a certified accountant: correspondence of the fields mentioned with the official table of the periodic VAT return, in the check against the AT's amounts.

Expected result

Notes with a reason feed the annexes and fields 40 and 41; the tag adjustment moves the amount to the correct field without touching the accounts; the check shows what differs. Each manual edit is recorded in Manual edits and in the audit log. The return simulation shows the effect before the period is closed.

Pending validation by a certified accountant: correspondence of the fields mentioned with the official table of the periodic VAT return, in the expected result.

Important notes

The list of divergences does not show everything

The Divergent fields counter on the October return shows 9, but the Divergences with the Tax Authority list shows 2 lines (fields 4 and 7). The other 7 are fields the system calculates (1, 2, 3, 90 to 93) that you did not enter in Tax Authority values. Use the counter as an alert and check the missing fields by hand.

Pending validation by a certified accountant: correspondence of the fields mentioned with the official table of the periodic VAT return, in the list of divergences.

Return already submitted

Editing the annexes, the AT's amounts and the manual fields is only possible in Draft and Computed. Once Validated, use Send back to draft (Fiscal administration); once submitted, the correction is a replacement return, with the Replace button. Pending validation by a certified accountant: when the adjustment in fields 40 and 41 replaces the replacement return (art. 78(6) and following).

Common problems

“needs a VAT adjustment reason”

• Symptom: you Confirm the note without a reason.
• What to do: choose the VAT regularization reason and confirm again.

The tag correction asks for the reason

• Symptom: Create adjustment entry without a Reason: “Some required fields are empty.”
• What to do: write the reason. With the correct tag the same as the wrong one: “Choose the wrong tag and a different, correct tag.”

“VAT return … was already submitted”

• Symptom: when recording an AT amount on a return already submitted: “VAT return “Empresa Demonstração, Lda — 2026/1 (v1)” was already submitted. What happened: the Tax Authority values are conferred before the submission. How to fix it: if the return needs correcting, use a replacement return.”
• What to do: create the replacement return.