Knowing what counts as an allowable business expense, and what doesn’t, is essential for healthy cash flow and accurate financial reporting. Getting it right means you can legitimately reduce your taxable profits and stay compliant with Revenue. Getting it wrong can mean penalties, overpaid tax, or a Revenue audit. This guide covers the golden rule for deductible expenses, common allowable costs, what isn’t deductible, and how to handle mixed-use items like your phone or car.
The Golden Rule
Revenue’s definition is clear: an expense must be “wholly and exclusively laid out for the purposes of the trade.” In practice, if the expense wouldn’t exist without your business, it’s likely allowable.
Before claiming, ask yourself: would I have spent this money if I wasn’t running my business? Is this expense directly linked to generating revenue or running operations? If the answer is yes, it usually qualifies. Always keep documentation (invoices, receipts, contracts) to prove the expense was business-related.
Common Allowable Business Expenses
- Office rent or home office costs: for home offices, claim a percentage of rent, utilities, and maintenance
- Software subscriptions: accounting tools, project management apps, and productivity software
- Accountant or bookkeeper fees: professional services like bookkeeping, financial advice, and accounting
- Internet and phone bills: the business-use percentage of your bills
- Business insurance: public liability, professional indemnity, and property insurance
- Marketing and advertising: website creation, branding, social media ads, and promotional campaigns
- Business mileage: travel for client meetings, events, or site visits, using Revenue’s mileage rates
- Travel and accommodation: hotel stays, flights, and meals when travelling for business
- Training and professional development: courses, workshops, or certifications relevant to your profession
Non-Deductible Expenses to Avoid
Certain costs are not allowable: client entertainment (concerts, sporting events), personal clothing (unless protective gear or a uniform), personal meals and groceries (unless directly linked to business travel or client meetings), entertainment subscriptions unless used for business content creation, gym memberships or personal health costs, and family-related expenses unless directly linked to business use. Claiming these can cause compliance issues.
Mixed-Use Items: How to Claim Correctly
Some expenses, like your phone, internet, or car, are used for both personal and business purposes. To claim correctly: calculate the exact business-use percentage, keep records of how you worked it out, and apply the same percentage consistently each month. This ensures your claims are accurate and defensible.
How to Track and Organise Your Expenses
Efficient recordkeeping is essential. Submit your documents through your agreed document-sharing process, so receipts and invoices stay securely organised. Categorise expenses (Marketing, Travel, Subscriptions, etc.) for easy tax filing. Our Monthly Bookkeeping Checklist covers this in more detail. If you’re a limited company, remember you must keep proper books and attach accurate financial statements when filing your annual return. See the CRO’s guidance on financial statement requirements. Flag uncertain items and seek advice before claiming anything unusual, since accurate records protect you during Revenue reviews.
Not Sure About a Claim?
If you’re ever uncertain, it’s always better to check first. A short conversation now can save time, money, and stress later, while making sure every claim is fully compliant.
Final Thoughts
Managing allowable business expenses properly gives you more financial breathing room and peace of mind. We help you track, categorise, and claim with confidence, so your business stays ready for tax season all year round.