Plain-English guides to UK Corporation Tax and CT600 filing.
Complete guide to HMRC penalties for Corporation Tax — late filing (from £100 fixed, rising to £200 for deadlines from April 2026, plus up to 20% of unpaid tax), late payment interest, and inaccuracy penalties. How to avoid them.
Need to file a CT600 for a period shorter than 12 months? Learn when short periods happen, how tax is calculated, financial year splits, and how to avoid HMRC rejection errors.
Made an error on your CT600? Learn exactly how to amend your corporation tax return, HMRC time limits, penalties for mistakes, and how to fix common CT600 errors step by step.
CT600 rejected by HMRC? Here are the most common rejection reasons — BVR errors, XML failures, mismatched data — and step-by-step instructions to fix and resubmit.
How iXBRL tagging works for CT600 filing — what gets tagged, HMRC requirements, common tagging errors, and how to generate iXBRL accounts without specialist software.
The most frequent errors company directors make when filing their CT600. From wrong dates to missing boxes — and how to get it right first time.