Do I need to calculate my own tax liability? Yes, you must complete the Self-Assessment calculation yourself (pages 32–33 of Form 11). FastTax.ie does this for you automatically. By Cathal Maxwell|2025-06-24T11:26:02+01:00May 23, 2025|Tax Return Self Assessment FAQs| Share This Story, Choose Your Platform! FacebookXBlueskyRedditLinkedInWhatsAppTelegramTumblrPinterestXingEmail About the Author: Cathal Maxwell Cathal brings over 40 years of tax experience, advising individuals and businesses on Income Tax, Capital Taxes, Inheritance Tax, Stamp Duty, and VAT.