Tax deductions
Learn what tax deductions are, which business expenses are allowable in Ireland, and how to claim them through Revenue.
Published Friday 24 July 2026
Table of contents
Key takeaways
- A tax deduction is a business cost you can subtract from your income to lower the income tax you pay to Revenue.
- Deductions and reliefs reduce your taxable income, while a tax credit reduces your final tax bill euro for euro.
- Common allowable expenses include rent, staff wages, business travel, professional fees and insurance, as long as they are wholly and exclusively for the business.
- You claim deductions through Revenue Online Service, using Form 11 if you are self-assessed or Form CT1 for a company.
Tax deductions (definition)
Understanding what counts as a deduction is the first step to lowering your tax bill. Here is the simple version before the detail.
A tax deduction (or allowable expense) is a business cost you can deduct from your income to reduce the amount of income tax you pay in Ireland. Revenue is the authority that sets the rules on which expenses qualify.
In practice, you add up your allowable business expenses and subtract them from your income. You then pay income tax on the lower figure, known as your taxable income.
Example of a tax deduction calculation
A worked example shows how a deduction changes the amount you are taxed on. Meet Jo, who runs a photography studio.
Jo earned €77,000 last year and had €15,000 of deductible expenses. So her taxable income is €62,000, and that lower figure is what Revenue taxes.
An expense qualifies only if it has a legitimate business purpose. A new camera is deductible for Jo because she uses it to earn income, but the same camera would not be deductible for a baker who has no business reason to buy it.
Tax deductions vs tax reliefs and tax credits
Deductions, reliefs and tax credits all lower what you pay, but they work in different ways. Knowing the difference helps you understand the saving from each.
A deduction or relief reduces your taxable income. Your saving equals the expense multiplied by your tax rate, so a €100 expense saves you €20 at the 20% rate, or €40 at the 40% rate.
A tax credit works differently: it reduces your final tax bill euro for euro. A €100 tax credit lowers the tax you owe by €100, whatever your rate.
Common tax-deductible business expenses in Ireland
Many everyday running costs count as allowable expenses if they relate to your business. The list below covers costs small businesses in Ireland claim most often.
- Rent, rates and utilities for your business premises
- Staff wages and salaries
- Business travel and motoring costs
- Professional fees, such as accountants and solicitors
- Business insurance
- Advertising and marketing
- Office equipment and supplies
- Business phone and broadband
The cost of assets like equipment or vehicles is usually claimed over several years through capital allowances, rather than all at once. To claim any of these costs, they must be incurred wholly and exclusively for the business, and you cannot claim personal expenses. You can read more about cover options in this guide to types of business insurance.
Claiming for costs that are part business and part personal
Some costs serve both your business and your personal life, so you cannot claim the full amount. In these cases you apportion the cost and claim only the business share.
Say you use a mobile phone for business 80% of the time. You can generally claim 80% of the cost as a deductible expense, and the remaining 20% stays personal.
Keep receipts and a clear record of how you worked out the split, so you can back up your claim if Revenue asks.
How to claim tax deductions through Revenue
You claim deductions when you file your annual tax return through Revenue Online Service (ROS). The steps below outline how it works for most small businesses.
- Sign in to Revenue Online Service (ROS) and open the tax return for the year you are filing.
- Choose the right return: self-assessed individuals use Form 11, and companies use Form CT1.
- Enter your allowable business expenses in the relevant sections so they reduce your taxable income.
- Keep your records and receipts in case Revenue asks you to support the figures.
Keep on top of your deductible expenses with Xero
Tracking expenses as you go means your deductible costs are ready when it is time to file, with less manual admin. Xero accounting software captures and categorises your costs in one place, and you can get one month free when you start.
FAQs on tax deductions
Here are answers to some frequently asked questions about tax deductions for small businesses in Ireland.
What is the difference between a tax deduction and a tax credit?
A tax deduction reduces your taxable income, so the saving depends on your tax rate. A tax credit reduces your final tax bill euro for euro.
What business expenses are tax-deductible in Ireland?
Costs incurred wholly and exclusively for your business are generally deductible, such as rent, staff wages, travel, professional fees and insurance. Personal expenses cannot be claimed.
Can you claim an expense used for both business and personal use?
Yes, but only the business portion. You apportion the cost and claim the share that relates to your business, keeping a record of how you worked it out.
How long do you have to claim a tax deduction?
Revenue applies a 4 year limit for claims. You generally have 4 years from the end of the relevant tax year to claim expenses or a refund.
Do you need receipts to claim tax deductions?
Yes, keep receipts and records for every expense you claim. Revenue can ask you to support your figures, so accurate records protect your claim.
Related Terms
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Disclaimer
This glossary is for small business owners. The definitions are written with their requirements in mind. More detailed definitions can be found in accounting textbooks or from an accounting professional. Xero does not provide accounting, tax, business or legal advice.