If you run a limited company, corporation tax in Ireland is the charge your company pays on its profits, and as a director, you carry personal responsibility for getting it right. Ireland’s headline 12.5% trading rate is one of the lowest in the developed world, but the rules around what counts as trading income, when to file and how much to pay on account can trip up even experienced owners. This guide explains the essentials in plain terms.
What corporation tax actually is
Corporation tax is a tax on the profits of a company that is resident in Ireland for tax purposes. It applies to limited companies, not to sole traders or partnerships, who pay income tax through self-assessment instead. If you have incorporated a business, switched from sole trader to a company or set up a new venture, your company is now a separate taxpayer with its own obligations to Revenue.
A company is generally tax-resident in Ireland if it is managed and controlled here, or in most cases simply by being incorporated here. Residence matters because an Irish-resident company is taxed on its worldwide profits, while a non-resident company is taxed only on Irish-source income. For most owner-managed Midlands businesses, residence is straightforward, but it is worth confirming if you have overseas directors or activities.
The 12.5% rate, and why it is not the whole story
The figure most people know is the 12.5% rate. This applies to trading income, the profits from your company’s normal business activity, whether that is a shop, a trade, a professional service or a manufacturing operation.
Two points are easy to miss:
- Non-trading income is taxed at a higher rate. Passive income such as rental profits, deposit interest and certain investment income is charged at 25%, not 12.5%. So a company with both a trade and a rental property has profits taxed at two different rates.
- A higher rate applies to large multinationals. Under the OECD global minimum tax rules, very large groups (broadly those with annual revenue above €750 million) face a minimum effective rate of 15%. This does not affect the typical Irish SME, which continues to benefit from 12.5% on its trading profits.
Capital gains made by a company, for example on selling a premises or shares, are dealt with separately and effectively taxed at the 33% capital gains tax rate. If a disposal is on the horizon, take advice early, as reliefs may be available.
Working out the tax bill
Corporation tax is charged on your company’s profits for an accounting period, which is usually twelve months and lines up with your financial year. The starting point is the profit shown in your accounts, but that figure is then adjusted for tax purposes. Common adjustments include:
- Adding back expenses that are not allowable for tax (such as client entertainment or depreciation)
- Claiming capital allowances in place of depreciation on equipment, fixtures and certain vehicles
- Applying any trading losses brought forward from earlier periods
- Claiming reliefs and credits your company qualifies for
One of the most valuable is the Research and Development (R&D) tax credit, which can significantly reduce the tax bill, or generate a refund, for companies developing new products, processes or software. There is also a start-up relief that can reduce or eliminate corporation tax in the early years for qualifying new trading companies. These reliefs have specific conditions, so it pays to check whether your company qualifies before you file.
The CT1 return and your filing deadline
Every Irish company files a corporation tax return called the CT1 through Revenue Online Service (ROS). The CT1 reports your company’s income, gains, deductions, reliefs and the tax due for the accounting period.
The return is due within a set window after your accounting period ends, under the current rules, generally by the 23rd of the ninth month following the period end, filing through ROS. So a company with a December year-end files its CT1 around the following September. Because exact dates and any extensions can change, confirm your own deadline with us or with Revenue rather than relying on a rule of thumb.
Late or incorrect filing carries real consequences. A surcharge applies to returns filed late, and persistent lateness can restrict the losses and other reliefs you are allowed to claim, which can cost far more than the surcharge itself. Poor records and missed returns also raise your risk of a Revenue audit. Filing on time and accurately is the cheapest tax planning there is.
Preliminary tax, paying before you file
Irish corporation tax works on a “pay and file” basis, which catches a lot of first-time directors. You do not simply wait until the return is due and then pay. You must pay preliminary tax, an estimate of the current year’s liability, before the accounting period ends, and then pay any balance when you file the CT1.
The amount of preliminary tax depends on the size of the company and is based on a percentage of either the current year’s expected liability or the previous year’s actual liability. Smaller companies have a simpler basis than larger ones. Getting the estimate wrong can lead to interest charges, so a mid-year review of expected profits is sensible. We will help you forecast it so there are no surprises on cash flow.
Director responsibilities beyond the tax itself
Corporation tax does not sit in isolation. As a director you also have to keep the company compliant with the Companies Registration Office (CRO), filing the annual return (Form B1) and financial statements on time. CRO and Revenue obligations run in parallel, and falling behind on one often signals trouble with the other. Our company secretarial services keep both sides in order, from company formation through to annual returns.
You should also keep proper books and records, retain them for the required period, and make sure directors’ loans, salaries and dividends are all handled correctly, each has its own tax treatment. Drawing money out of your company is rarely as simple as it looks, and the wrong approach can create an unexpected personal tax charge.
Getting it right with the right support
For most owner-managed companies, corporation tax is very manageable with good records and timely advice. The areas that cause problems are usually the predictable ones: missing the CT1 deadline, underpaying preliminary tax, mixing up trading and non-trading income, or overlooking a relief the company was entitled to claim.
Our corporation tax service handles the full cycle for Irish companies, preparing the computations, filing the CT1 through ROS, managing preliminary tax and making sure every available relief is claimed. We work with companies from our offices in Athlone and Trim and across the wider Midlands, as well as clients throughout Ireland.
If you are unsure about your company’s position, your next deadline or whether you are paying more tax than you need to, we would be glad to help. Book a free consultation and we will review your situation and set out clear, practical next steps.