Last updated: 14 October 2026
Does your company have to submit accounts and a corporation tax return?
Yes. Every UK limited company must file annual accounts at Companies House, even if it is dormant. It must also file a corporation tax return (CT600) with HMRC if it is trading, or if HMRC sends it a notice to deliver a return. A dormant company that HMRC has been told is dormant usually doesn’t need to file a CT600, but it still files dormant accounts and a confirmation statement.
Filing obligations
| Filing | Who | Deadline |
| Annual accounts (Companies House) | All companies | 9 months after the year-end (21 months after incorporation for the first accounts) |
| CT600 return (HMRC) | Active companies, or any company sent a notice | 12 months after the end of the accounting period |
| Corporation tax payment | Companies with taxable profits | 9 months and 1 day after the end of the period |
| Confirmation statement | All companies | Within 14 days of the review date |
What a CT600 includes
- The CT600 form
- Tax computations showing how profits were adjusted for tax
- Accounts in iXBRL format
Since 1 April 2026, you must use commercial software to file it, because HMRC’s free online service has closed.
Dormant companies
A company is dormant for corporation tax if it has no income and isn’t trading. Tell HMRC within 3 months if the company becomes dormant. HMRC may then not ask for a return. You still file dormant company accounts at Companies House.
Penalties
| Late filing | Companies House penalty (private company) | HMRC penalty |
| Up to 1 month | £150 | £100 if 1 day late |
| 1 to 3 months | £375 | £100 more after 3 months |
| 3 to 6 months | £750 | 10% of unpaid tax after 6 months |
| Over 6 months | £1,500 | A further 10% after 12 months |
Companies House penalties double if accounts are late two years in a row. These amounts are taken from Companies House’s late filing penalties guidance on gov.uk (updated January 2026).
Example
A company with a 31 March 2026 year-end must file accounts at Companies House by 31 December 2026, pay corporation tax by 1 January 2027 and file its CT600 by 31 March 2027.
Changes coming in April 2028
From 1 April 2028, all companies must file accounts with Companies House using software, and abridged accounts will end.
Tips for filing accounts and returns on time
Register for Companies House email reminders and diary both the accounts deadline (9 months after the year-end for private companies) and the CT600 deadline (12 months). Send your bookkeeping to your accountant at least 3 months before the Companies House deadline, so there is time to review the figures and sign the accounts.
Frequently asked questions
Do I need an accountant?
No, but most directors use one to prepare the accounts, computations and iXBRL filing.
Does a company with a loss still file?
Yes. Filing also records the loss for future use.
What if I can’t file on time?
Apply to Companies House for an extension before the deadline, if you have a good reason.
Do I need to file if the company is closing?
Yes, until it is struck off or liquidated.
Related: MTD for corporation tax and preparing year-end accounts.
Talk to Accotax
Want this handled for you? Our team at Accotax can help with company accounts and tax returns. See our limited company accountants service, or contact us for a free, no-obligation quote.
This page is general guidance based on HMRC rules for the 2026/27 tax year, checked against gov.uk on 14 October 2026. It is not personal advice, so speak to an accountant about your own situation.
