Guides
The parts of Irish VAT and invoicing that catch small businesses out, written plainly. We had to make the software get these right, which is a good way to find out where the rules actually bite.
When is my VAT3 due? Irish VAT deadlines for 2026 and 2027
Every Irish two-monthly VAT period and the date the return and payment are due on ROS, for 2026 and 2027. Plus what to do if you file quarterly, four-monthly, half-yearly or annually.
Reverse charge invoices in Ireland: what the document must say
When you invoice with no VAT under the reverse charge - EU B2B services, or construction subcontracting to a principal contractor - the invoice itself has to carry three things. Here they are, with the exact wording.
The VAT3 return: where your T1 figure comes from
T1 is VAT on your sales for the period. What goes into it depends on whether you file on the invoice basis or the cash receipts basis - and the two give genuinely different answers for the same set of invoices.
A credit note belongs to the period you issued it
Reversing a sale from a previous VAT period does not reopen that period. The credit note lands in the period it was issued - and the difference between that and deleting the invoice is real money on a return you have already filed.
Deposit invoices: one document, two payments
Asking for half up front should not mean raising two invoices and remembering to send the second. Here is how a deposit works on a single document, and what it means for the VAT depending on which basis you file.