CT600 Deadline: When to File Your Corporation Tax Return (and When to Pay)
When is your CT600 due? Filing deadlines, payment deadlines, and how they differ from Companies House deadlines. Avoid late penalties.
Plain-English guides to UK Corporation Tax and CT600 filing.
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.
How dividends interact with Corporation Tax — paying dividends, receiving dividends, the dividend exemption, franked investment income, and CT600 reporting for UK companies.
How to claim capital allowances on your CT600 — AIA, writing down allowances, full expensing, first-year allowances, and which assets qualify for Corporation Tax relief.
All corporation tax deadlines for 2026 — CT600 filing dates, payment due dates, and penalties for late filing. Key dates for UK limited companies.