How to Pay Corporation Tax: Complete HMRC Payment Guide 2025/26
Step-by-step guide to paying your corporation tax bill. Covers all payment methods, deadlines, payment references, and what happens if you pay late.
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Plain-English guides to UK Corporation Tax and CT600 filing.
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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.
HMRC Free Filing Has Closed: What to Use Instead
HMRC's free CT600 filing service closed on 31 March 2026. Step-by-step guide to choosing a replacement and filing your Corporation Tax return.
Best Alternatives to HMRC's Free Filing Service in 2026
HMRC's free CT600 filing tool closes March 2026. Compare the best alternatives: Taxpipe (£59), accountants, and full accounting software for UK limited companies.
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.
CT600 Box-by-Box Guide: Every Core Box Explained (2025/26)
Complete walkthrough of every CT600 box from 1 to 620. Plain English explanations, what to enter, and which boxes most small companies actually use.
Corporation Tax Losses: How to Carry Forward and Offset Against Future Profits
How to carry forward trading losses on your CT600 to reduce future corporation tax bills. Box references, time limits, and practical examples.
Dormant Company Corporation Tax: Do You Need to File a CT600?
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.
VAT Registration and Corporation Tax: How They Interact
Learn how VAT registration affects your Corporation Tax return, including input tax recovery, flat rate scheme profits, and what goes on your CT600.
What Happens If Your Accounting Period Is Longer Than 12 Months?
HMRC splits accounting periods over 12 months into two, requiring two CT600 returns. Learn how to calculate tax for each period.
R&D Tax Relief for SMEs: How the Merged Scheme Works and How to Claim on Your CT600
Understand the merged R&D tax relief scheme for SMEs from April 2024, qualifying expenditure, credit rates and reliefs, and which CT600 boxes to complete.
HMRC Rejected Your CT600? Common Errors and How to Fix Them
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.