What must be on a valid invoice in Ireland (and when to register for VAT)

A valid invoice does two jobs: it gets you paid, and it keeps Revenue happy. For a sole trader most of it is common sense, but a few fields are not optional — and the accounts office of a bigger customer will bounce an invoice that is short of them.

What has to be on the invoice

At a minimum, your invoice should carry:

• Your name or trading name and address, and your VAT number if you are registered.
• A unique sequential invoice number — no gaps, no duplicates.
• The date of issue, and the supply date if it is different.
• The customer's name and address.
• A clear description of the work and materials.
• The amount due — and if you are VAT registered, the VAT rate and amount shown separately for each rate.

Sequential numbering matters more than people think. A Revenue auditor reads gaps in your invoice numbers as invoices you forgot to declare, so let the numbering run on its own rather than typing it by hand each time.

When you must register for VAT

You must register once your turnover passes the threshold — €42,500 for services in 2025, with a higher figure for goods. Below that you can register voluntarily, but you do not have to. Once you cross it, registration is not a choice.

Once registered, you charge VAT — 13.5% on most construction work, 23% standard — and you can reclaim the VAT on your own purchases. For business-to-business construction the reverse charge can move the VAT onto the principal contractor instead; that is its own topic, covered in the construction VAT reverse charge guide.

Invoicing when you are not VAT registered

If you are under the threshold and not registered, it is simpler: you do not charge VAT and you do not show a VAT rate or a VAT number. Do not add a "0%" VAT line that makes it look like you are registered — just leave VAT off and invoice the agreed amount for the work. Keep the same numbering and the same level of detail; the only difference is the VAT.

The mistakes that hold up payment

No job or purchase-order reference

Bigger customers pay against a reference. Ask for the PO or job number up front and put it on the invoice, or you go to the bottom of the pile in the accounts office.

Vague descriptions

"Building work — €3,000" invites questions and slows the payment. List the work and the materials so there is nothing for anyone to query.

Charging VAT you are not registered to charge

If you are not registered, you cannot add VAT to the bill. Doing it anyway is a fast way to a problem with both your customer and Revenue — sort the registration first, then charge it.

Get paid faster by giving the accounts office nothing to query: your details, a clean number, a clear description, and VAT shown correctly — or not at all.

How to make it automatic

MarginTap puts your details, the next sequential number and the right VAT treatment on every invoice — including the reverse-charge wording when a job qualifies — so a valid invoice is the default, not a checklist you run on a Friday night. Quote on site, convert the accepted quote to an invoice, and send it before you leave.

[ See how MarginTap handles invoices → ]

None of this replaces advice from your own accountant or Revenue — thresholds move and your situation may have a wrinkle this guide does not cover. Next, see how to quote a job without underpricing yourself.