How to Amend a CT600 Tax Return: Correcting Mistakes After Filing
Made an error on your CT600? Learn how to amend your corporation tax return within the 12-month deadline, what changes HMRC allows, and the step-by-step process.
Plain-English guides to UK Corporation Tax and CT600 filing.
Made an error on your CT600? Learn how to amend your corporation tax return within the 12-month deadline, what changes HMRC allows, and the step-by-step process.
HMRC's free CT600 filing tool closes March 2026. Compare the best alternatives: Taxpipe (£59), accountants, and full accounting software for UK limited companies.
HMRC's free CT600 filing service closes March 2026. Step-by-step guide to choosing a replacement and filing your Corporation Tax return.
When is your CT600 due? Filing deadlines, payment deadlines, and how they differ from Companies House deadlines. Avoid late penalties.
Complete walkthrough of every CT600 box from 1 to 620. Plain English explanations, what to enter, and which boxes most small companies actually use.
How to carry forward trading losses on your CT600 to reduce future corporation tax bills. Box references, time limits, and practical examples.
Find out if your dormant company must file a CT600 with HMRC. When you're exempt, when you must file, and how to submit a nil return.
Learn how VAT registration affects your Corporation Tax return, including input tax recovery, flat rate scheme profits, and what goes on your CT600.
HMRC splits accounting periods over 12 months into two, requiring two CT600 returns. Learn how to calculate tax for each period.
Understand the merged R&D tax relief scheme for SMEs from April 2024, qualifying expenditure, enhanced rates, and which CT600 boxes to complete.
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.