The rhythm: bi-monthly, due on the 23rd
The default filing pattern is six two-month periods per year: Jan–Feb, Mar–Apr, May–Jun, Jul–Aug, Sep–Oct, Nov–Dec. The return and payment are due by the 19th of the following month — stretched to the 23rd if you file and pay through ROS, which in practice everyone does. Smaller businesses can be moved to four-monthly, six-monthly or annual filing by Revenue; larger traders sometimes file monthly.
The four boxes that matter
| Box | What goes in it |
|---|---|
| T1 | VAT charged on your sales in the period |
| T2 | VAT you’re reclaiming on business purchases |
| T3 | VAT payable: T1 − T2, when T1 is bigger |
| T4 | VAT repayable to you: T2 − T1, when T2 is bigger |
(E1/E2 and ES1/ES2 cover intra-EU goods and services — they matter for importers and exporters, and are zero for a purely domestic trader.)
Where the calculator earns its keep
Building T1 and T2 means extracting the VAT from a pile of gross receipts — and that’s where people subtract 23% instead of dividing by 1.23 and quietly overstate their reclaim. Run each gross amount through the remove-VAT mode: it divides correctly for every Irish rate, including 13.5% fuel and repair receipts, and the 13.5%/9% mix on hospitality bills.
The RTD: the return everyone forgets
Once a year, alongside your normal cycle, Revenue expects the Return of Trading Details — an annual breakdown of sales and purchases by VAT rate. No payment attaches to it, so it feels optional. It isn’t: an outstanding RTD blocks VAT refunds and tax clearance certs. It’s ten minutes in ROS if your bookkeeping is clean.
Three mistakes Revenue actually notices
- Reclaiming VAT that was never reclaimable — entertainment, most food and drink, and passenger cars (with narrow exceptions) don’t qualify, no matter what the receipt says.
- Missing nil returns — quiet period, no return filed, automatic reminder letter, then estimates. File the nil.
- Round-number returns — T1 and T2 ending in suspiciously many zeros, period after period, invites a closer look. Real books produce ragged numbers.
Frequently asked questions
When is the VAT3 return due?
For bi-monthly filers, the 19th of the month after the period ends — extended to the 23rd when you file and pay through ROS (which almost everyone does). The Jan–Feb period is due 23 March, Mar–Apr due 23 May, and so on.
What are T1, T2, T3 and T4 on the VAT3?
T1 is VAT charged on your sales. T2 is VAT you’re reclaiming on purchases. T3 is VAT payable (T1 minus T2 when positive). T4 is VAT repayable to you (when T2 is bigger than T1).
What is the RTD?
The Return of Trading Details — an annual summary of all your supplies and purchases broken down by VAT rate. It’s a statistics return (no payment), but Revenue can withhold refunds and tax clearance if it’s outstanding.
Do I file a VAT3 if I had no sales?
Yes. A nil return is still a return — skipping periods with no activity is one of the fastest ways to collect penalty letters.