RCT Relevant Contracts Tax Guide Ireland

RCT Relevant Contracts Tax: A Plain-English Guide for Irish Contractors and Subcontractors

If you work as a principal contractor or a subcontractor in the Irish construction sector, RCT relevant contracts tax is probably the single most confusing part of your tax life. It sits alongside your normal VAT and income tax obligations, has its own registration process, its own deduction rates, and its own reverse charge rules for VAT. Get it wrong and you can end up with cash withheld unexpectedly, or a penalty for a contract you forgot to notify. Get it right and RCT becomes a routine background process that barely touches your day-to-day invoicing. This guide walks through what RCT is, who it applies to, how the deduction rates work, how the construction reverse charge for VAT interacts with it, and how to keep your books under your own control while staying compliant with Revenue.

What is RCT relevant contracts tax?

RCT relevant contracts tax is a withholding tax system that applies to payments made under "relevant contracts" - principally in the construction industry, but also extending to forestry and meat processing operations . It exists because subcontractor chains in construction have historically been a high-risk area for unpaid tax, so Revenue built a system where the principal contractor (the business paying for the work) is responsible for deducting tax at source from payments to subcontractors, based on the subcontractor's compliance record with Revenue.

Two roles matter here:

  • Principal contractor - the business engaging a subcontractor to carry out construction operations under a "relevant contract".
  • Subcontractor - the business or individual carrying out the work for the principal.

The same business can be both a principal and a subcontractor at different points on the same job - a common scenario in construction where work is subcontracted down through several tiers.

Who needs to register for RCT?

If you are a principal contractor engaging subcontractors on relevant contracts, you must register for RCT with Revenue and operate the system through the Revenue Online Service (ROS). Subcontractors don't "register" for RCT in the same sense, but their tax reference number and compliance history determine the deduction rate applied to them - which is exactly why keeping your own tax filings current matters even if you're only ever the subcontractor in the relationship.

Before work begins, the principal contractor must notify Revenue of the contract details through ROS. This isn't optional paperwork you can skip if the job is small or short - failure to notify a contract correctly is one of the most common ways businesses fall foul of RCT.

How RCT deduction rates work

Once a contract is notified, Revenue assesses the subcontractor and returns a deduction rate to the principal contractor. There are three possible outcomes: a 0% rate (no deduction), a 20% standard rate, and a 35% higher rate for subcontractors who are not fully tax compliant or not known to Revenue . The principal contractor is legally obliged to deduct at the rate Revenue specifies - they cannot negotiate it, ignore it, or apply their own judgement.

Practically, this means:

  • The principal makes a payment notification to Revenue before paying the subcontractor.
  • Revenue responds with a deduction authorisation confirming how much tax to withhold.
  • The principal pays the subcontractor the net amount and remits the deducted tax to Revenue.
  • The subcontractor can see the deduction on their own ROS record and offset it against their eventual income tax or corporation tax liability.

For subcontractors, keeping a good compliance record - filing income tax returns and VAT3 returns on time, paying what's due - is what keeps the deduction rate low. This is one of the quieter reasons RCT ties so closely into your wider bookkeeping: a business that's behind on its VAT3 return or its annual return can find itself facing a higher RCT deduction rate on every payment it receives, which is a direct hit to cash flow.

RCT and the construction reverse charge for VAT

Alongside RCT sits a separate but related mechanism: the domestic reverse charge for VAT on construction services. Where it applies, the subcontractor does not charge VAT on their invoice to the principal contractor. Instead, the principal contractor accounts for the VAT themselves under the reverse charge - a mechanism set out under Section 16 of the VAT Consolidation Act 2010 and in place for construction services since 1 September 2008 - typically self-cancelling out in the same VAT3 return where they're entitled to full deduction . This is a different mechanism from RCT itself - RCT is a withholding tax on the payment; the reverse charge is a VAT treatment on the invoice - but the two frequently apply to the same relevant contract, and invoices in the construction sector often need to show both a nil VAT charge with a reverse charge note, and be correctly flagged for RCT payment notification purposes.

This is exactly where invoicing software that understands Irish VAT rules earns its keep. Getting the reverse charge wording wrong on an invoice, or charging VAT when you shouldn't have, creates a mess for both sides that usually ends up costing time to unwind with Revenue or with your accountant.

Common RCT mistakes to avoid

  • Not notifying a contract before work starts. Notification is meant to happen in advance, not retrospectively once you realise you should have.
  • Charging VAT on a reverse-charge invoice, or leaving VAT off an invoice that should carry it. The two systems (RCT and reverse charge VAT) look similar but are governed separately.
  • Letting your own VAT3 or income tax filings slip. A poor compliance record with Revenue can push your RCT deduction rate up, even if the actual job you're being paid for has nothing to do with the missed filing.
  • Treating RCT paperwork as separate from your everyday invoicing. The businesses that struggle most with RCT are the ones running it as a bolt-on spreadsheet exercise disconnected from their normal books, rather than as part of one continuous record.

Keeping control of your books while RCT runs in the background

None of this means construction businesses need to hand every scrap of financial data over to a third party just to stay compliant. WDI Billing is built around three modes - Records, Prepare, and File - with Prepare as the default. Your invoices, receipts and RCT-related documentation sit in your own records; when it's time to prepare a VAT3 return or reconcile RCT deductions against what Revenue has confirmed, Prepare mode gets everything ready to check. Nothing streams automatically to Revenue or to ROS - you press file. That distinction matters in an industry where subcontractor payments, deduction rates and reverse charge VAT can all shift from job to job, and where you want to see the numbers before anything is submitted, not after.

Because WDI Billing is euro-native and built with Irish VAT treatment in mind, invoices for relevant contracts can carry the correct reverse charge presentation without you needing to remember the wording every time. And because your data is held under GDPR with EU residency, moving between an accountant, a bookkeeper, or your own filing doesn't mean your books leave your control - you can grant break-glass access to an accountant for a review of RCT and VAT3 positions without giving away permanent, unmonitored access to everything you hold.

Where RCT fits with your wider VAT position

RCT rarely sits in isolation. Most principal contractors and subcontractors affected by it are also dealing with standard VAT registration thresholds, VAT3 returns, and ROS filing deadlines on the rest of their business. If you haven't already, it's worth reading our guides on how to file a VAT3 return and using the Revenue Online Service (ROS) to understand how RCT deductions and reverse charge VAT entries feed into your regular filing cycle. If you're newer to VAT registration generally, our guide to VAT registration in Ireland covers the thresholds and process from scratch.

Software built for how Irish construction businesses actually invoice

Whether you're a principal contractor managing payment notifications for a handful of subcontractors, or a subcontractor invoicing under the reverse charge and tracking RCT deductions against your own tax position, the right invoicing and VAT software should make the reverse charge treatment automatic rather than something you have to remember on every invoice. Our VAT software for Ireland is built for ROS-ready VAT3 returns, and our invoicing software handles euro-native billing with the reverse charge and RCT-aware invoice fields construction businesses need - no per-invoice fees, no lock-in, and your records stay yours.

Get RCT and reverse charge VAT under control

RCT relevant contracts tax doesn't have to be a source of dread every time you submit a payment notification or reconcile a deduction. With the right invoicing set-up, reverse charge VAT treatment and RCT documentation become a routine part of your books rather than a separate headache bolted on at year-end. Try WDI Billing free and see how Prepare mode, euro-native invoicing, and GDPR-based data residency work together for Irish construction businesses - you stay in control, and nothing goes to Revenue until you decide to press file.