The trading income rate is 12.5%, one of the lowest in the OECD. Non-trading income (rental, investment, passive income) is taxed at 25%. The R&D tax credit provides an additional 25% reduction on qualifying R&D expenditure.

Trading income comes from your company's core business activities — selling goods or services. Non-trading income includes passive income sources like rental income, investment interest, dividend income, and gains on non-trading assets.

The R&D tax credit provides a 25% credit on qualifying research and development expenditure. The credit can be used to reduce your Corporation Tax liability. If the credit exceeds your CT liability, SMEs can claim the excess as a payable credit over three years.

Preliminary tax is due one month before the end of your accounting period (or 6 months before for larger companies with a CT liability over €200,000). The balancing payment is due 9 months after the year end.

Corporation Tax returns are filed through Revenue's ROS system using Form CT1. The return is due within 9 months of the end of your accounting period. You must file online.

The effective rate depends on your mix of trading and non-trading income, and any R&D credits. A company with only trading income pays 12.5%. With R&D credits, the effective rate can be significantly lower. This calculator shows your effective rate based on your inputs.

Most revenue expenses incurred wholly and exclusively for the purposes of the trade are deductible, including salaries, rent, utilities, marketing, professional fees, and interest on business loans. Capital expenditure is generally not deductible but may qualify for capital allowances.

Close companies (controlled by 5 or fewer people) may be subject to a 20% surcharge on certain undistributed investment income and rental income. This is to prevent the accumulation of passive income within a company rather than distributing it to shareholders.

Yes, trading losses can be carried forward indefinitely against future trading profits of the same trade. You can also claim relief in the current year against other income, or carry back losses one year against profits of the same trade.

Ireland has OECD-compliant Transfer Pricing rules requiring transactions between connected companies to be at arm's length. This applies to trading transactions and now also to loans and other financial transactions for periods beginning on or after 1 January 2025.

Ireland has a participation exemption for certain foreign dividends and gains on disposals of shares in subsidiaries, provided the company holds at least 5% of the shares and the subsidiary is resident in a treaty country or is subject to a 12.5%+ tax rate.

Irish companies paying dividends, interest, and royalties to residents of treaty countries may be subject to reduced withholding tax rates under the relevant Double Taxation Agreement. The standard rates are 25% (dividends) and 20% (interest/royalties).