HMRC Free CT600 Filing Service Has Closed: What Directors Must Do Now
HMRC's free CT600 filing service closed permanently on 31 March 2026. Here's your complete action plan — deadlines, penalties, and the most affordable alternative at £59.
Blog
Plain-English guides to UK Corporation Tax and CT600 filing.
Best CT600 Software for Limited Companies (2026 Comparison)
Comparing the best CT600 corporation tax software for UK limited companies in 2026. Pricing, features, and which one is right for your business.
How to File CT600 Online in 2026: Complete Step-by-Step Guide
HMRC's free filing service closed on 31 March 2026. Here's exactly how to file your CT600 corporation tax return online in 2026 — step by step, with tips and common mistakes to avoid.
Company Director Tax Responsibilities: What You Must Do (and When)
Every UK company director has legal tax obligations. This checklist covers corporation tax, PAYE, VAT, confirmation statements, and key deadlines.
CT600 Supplementary Pages: Which Ones Does Your Company Need?
Not sure which CT600 supplementary pages to file? This guide explains each page — CT600A to CT600J — and tells you exactly which ones your company needs.
Full Expensing: 100% Capital Allowances Made Permanent (2025 Guide)
Full expensing lets your company deduct 100% of qualifying plant and machinery costs immediately. Here's who qualifies, what's included, and how to claim on your CT600.
HMRC Free CT600 Filing Ended March 2026: What Are Your Options?
HMRC's free Corporation Tax Online service closed 31 March 2026. Here's what changed and the cheapest ways to file your CT600 now that the free option is gone.
UK Corporation Tax Rates 2025/26: Complete Guide with Examples
Corporation tax rates for 2025/26: 19% small profits rate, 25% main rate, and marginal relief in between. Includes worked examples and thresholds.
CT600 Box 155: Trading Profits — What Goes Here and How to Calculate It
Box 155 is the most important number on your CT600. Learn exactly what trading profits means, how to calculate it, and common mistakes to avoid.
What Is iXBRL? Inline XBRL Explained Simply for Company Directors
HMRC requires iXBRL for CT600 accounts and tax computations. What is it, why does it matter, and how do you create it? Plain English guide for directors.
How to Get a Corporation Tax Refund from HMRC (Overpayment Guide)
Overpaid corporation tax? Learn how to claim a refund from HMRC, how long it takes, and what to do if your refund is delayed.
Filing Annual Accounts at Companies House: Complete Guide for Limited Companies
Everything you need to know about filing your company's annual accounts at Companies House — deadlines, formats, micro-entity vs small company, and penalties.