How to Use HMRC Government Gateway to File Your CT600
Step-by-step guide to setting up and using your HMRC Government Gateway account to file your CT600 Corporation Tax Return online.
Plain-English guides to UK Corporation Tax and CT600 filing.
Step-by-step guide to setting up and using your HMRC Government Gateway account to file your CT600 Corporation Tax Return online.
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.
Owe money to your company? Learn how an overdrawn director's loan account triggers S455 tax on your CT600, how much you'll pay, and how to get it back.
Full 2026 calendar of Corporation Tax deadlines — CT600 filing dates, payment due dates, penalty dates, and quarterly instalment dates month by month.
How is rental income taxed in a limited company? Learn how property income works on your CT600, allowable deductions, and when a property company makes sense.
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.
Is your limited company a close company? Learn what it means for corporation tax, S455 tax on loans, and how it affects your CT600 filing.
Which expenses can't you deduct on your CT600? Complete guide to disallowable expenses for corporation tax — entertaining, fines, personal costs, and more.
Should you pay an accountant or file your CT600 yourself? An honest comparison of costs, time, risks, and when each option makes sense for UK limited companies.
Trading losses, non-trading deficits, capital losses — learn the different types of company loss, how each is relieved, and where they go on your CT600.
How the Flat Rate VAT Scheme affects your corporation tax. Learn about the VAT surplus, how to report it on your CT600, and whether the scheme still saves money.
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.