myDATA is not a replacement for accounting records.
IAPR/AADE describes myDATA as part of the automation of tax-return preparation, while also making clear that businesses continue to maintain their own accounting records and that the accountant remains critical to the correct tax representation of transactions.
From 1 January 2025, tolerated VAT-return deviations have ceased.
myDATA data is used to prefill output VAT, input VAT and related return fields. The revenue–expense rule applies to VAT periods from 1 January 2024.
Decision A.1108/2024 progressively reduced permitted deviations during 2024 and provides that from 1 January 2025 onward there are no permitted VAT-return deviation limits against the corresponding data transmitted to myDATA.
The annual tax-form rule is different.
For the E3 form, revenue and expense categories are prefilled from transmitted and classified myDATA data. Decision A.1045/2025 sets tolerated differences at 30% for revenue and 30% for purchases/expenses per tax year.
What should actually reconcile
- accounting records ↔ myDATA,
- revenue ↔ output VAT,
- expenses ↔ input VAT,
- classifications ↔ E3 categories,
- retail flows ↔ eSend / fiscal devices ↔ myDATA where applicable,
- credit notes and cancellations ↔ final accounting treatment.
Where differences usually arise
Common sources include missing or late transmissions, incorrect classifications, credit-note/cancellation mismatches, period-cut-off differences and discrepancies between retail accounting data and the eSend–myDATA flow.
From technical obligation to finance control
A practical monthly review should identify failed transmissions, book-to-myDATA revenue differences, unclassified expenses, VAT mismatches and unresolved corrections before the monthly close.
Connecting digital tax data to the finance function
Within Accounting & Tax, myDATA reconciliation is part of the recurring tax and accounting cycle. More complex mappings and system flows can be addressed through Digital Tax Operations, while historical discrepancies may require Accounting Clean-Up & Tax Remediation.
This Brief is for information only and does not replace a review of the actual accounting, tax and systems data of a specific business.