Company Formation & Corporation Tax Registration
Step-by-step guide to registering for Corporation Tax after forming a limited company. Covers CT41G, UTR numbers, deadlines, and first CT600 filing.
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Plain-English guides to UK Corporation Tax and CT600 filing.
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Corporation Tax Deadlines Calendar 2026
Full 2026 calendar of Corporation Tax deadlines — CT600 filing dates, payment due dates, penalty dates, and quarterly instalment dates month by month.
Corporation Tax for Investment Companies
How does corporation tax work for investment companies? Guide to holding investments through a limited company — dividends, capital gains, property, and filing your CT600.
Corporation Tax for Small Businesses: 2026
Complete 2026 guide to corporation tax for small businesses. Covers rates, allowable expenses, filing deadlines, payment dates, and tips to reduce your tax bill legally.
CT600 Filing Agent Authorisation with HMRC
How to authorise an agent to file your CT600. Step-by-step guide to HMRC agent authorisation for corporation tax — online, by post, and what to do if things go wrong.
HMRC CT600 Online vs Software: Which Is Better?
HMRC's free CT600 online filing service closed on 31 March 2026. Compare what it offered against commercial software, and see what your filing options are now.
HMRC Penalties for Late Corporation Tax Filing
What are the penalties for filing your CT600 late? Understand HMRC penalty rates, interest charges, and how to avoid or appeal late filing penalties.
How to Appeal a CT600 Late Filing Penalty from HMRC
Got a CT600 late filing penalty? You may be able to appeal. Step-by-step guide to HMRC penalty appeals, reasonable excuses, and time limits.
Free CT600 Filing Software: What Are Your Options in 2026?
Free CT600 filing software compared. HMRC's free filing service closed in March 2026 — here's what it offered and what to use instead.
CT600 for Contractors: Filing When You're Inside or Outside IR35
How IR35 status affects your CT600. Practical guide for contractors filing corporation tax — inside IR35, outside IR35, or mixed.
Making Tax Digital for Corporation Tax: What Your Company Needs to Know
HMRC cancelled Making Tax Digital for Corporation Tax in July 2025. Here's what happened, what it means for your company, and what filing changes do affect you now.
Corporation Tax for Startups: The Complete Guide for New Limited Companies
Corporation tax for startups. Registration, deadlines, expenses, R&D relief, first CT600 filing, and mistakes to avoid.