Do I need to file a corporation tax return (CT600) as well as accounts?
Yes. Almost every active limited company must file a CT600 corporation tax return with HMRC, in addition to filing statutory accounts with Companies House. The two filings use the same underlying financial information but go to different bodies, on different deadlines.
Your CT600 reports your company's taxable profit and calculates the corporation tax due for the period, after applying any reliefs and allowances your company is entitled to.
When is my CT600 due, and when do I pay corporation tax?
Your CT600 must be filed online with HMRC within 12 months of the end of your accounting period. However, any corporation tax owed must be paid earlier, 9 months and 1 day after your accounting period ends, so the payment deadline comes before the filing deadline.
Missing the CT600 filing deadline triggers an automatic £100 penalty, with another £100 added if you're still more than 3 months late, and further penalties of 10% of any unpaid tax at 6 and 12 months late.
How submitting corporation tax alongside your accounts works
Because your CT600 is built from the same figures as your statutory accounts, we prepare both together rather than as two separate jobs. This reduces the risk of inconsistencies between what's reported to Companies House and what's reported to HMRC, and means you only need to send us your records once.
Once your accounts are finalised and you've approved them, we prepare the CT600, calculate the tax due, and submit both filings within the same engagement.
What is the final corporation tax return for a company that's closing?
A final corporation tax return covers the last accounting period before your company stops trading or is dissolved, and often needs to be filed to a shortened period rather than your usual 12 months. HMRC needs this final CT600 to close your company's tax record properly.
If you're planning to close your company, tell us early so we can prepare accounts and the final CT600 to the correct dates and avoid delays to the closure process.
What are year end accounts for a limited company?
Year end accounts are the statutory financial statements a limited company must prepare covering its accounting period, typically including a balance sheet and notes, filed with Companies House. They form the starting point for your CT600 corporation tax calculation.
For periods starting on or after 6 April 2025, a company qualifies as a micro-entity with turnover of £1 million or less, a balance sheet total of £500,000 or less and 10 or fewer employees (meeting two of three), or as small with turnover of £15 million or less, a balance sheet total of £7.5 million or less and 50 or fewer employees.
Can I file my company accounts myself?
Yes, directors can prepare and file both accounts and a CT600 themselves, and many small companies do. The challenge is usually not the filing mechanics but getting the accounting treatment and available reliefs right, which is where an accountant adds the most value.
From April 2028, Companies House is moving to software-only filing for accounts, and small and micro companies will need to file a profit and loss account with the option to opt out of it being made public, with abridged accounts being removed. Any Companies House fee shown is charged at today's rate; if Companies House changes it, we charge the new fee separately. We are an independent firm of Chartered Accountants, not Companies House or HMRC.