Planned downtime from from 7am on Saturday 24 May 2025 to 8am on Monday 26 May 2025 has been added.

Planned downtime from 5pm on Friday 4 April 2025 to 10am Monday 7 April 2025 has been added.

A service issue about the Corporation Tax online service has been added.

Planned downtime from 8am to 6pm on Sunday 8 September 2024 has been added.

The service issue about delays in receiving return submission responses has been resolved.

Planned downtime from 8am to 6pm on Saturday 8 June 2024 has been added.

A service issue about accessing the Corporation Tax online service has been added.

The service issue about delays in receiving return submission responses has been resolved.

On Friday 5 April 2024 from 11:59pm to 11am on Monday 8 April 2024 the free online filing service will be unavailable. On Friday 10 May 2024 from 4pm to 8am on Monday 13 May 2024, the ability to register for Corporation Tax will be unavailable.

Planned downtime from 4pm on Friday 10 May 2024 to 8am Monday 13 May 2024 and from 11:59pm on Friday 5 April 2024 to 11am on Monday 8 April 2024 has been added.

Planned downtime from 8pm on Sunday 3 March 2024 to 1am Monday 4 March 2024 has been added.

Planned downtime planned from 6pm on Friday 24 November 2023 to 9pm Sunday 26 November 2023 has been extended, and now ends at 6am Monday 27 November.

Planned downtime from 6pm on Friday 24 November 2023 to 9pm Sunday 26 November 2023 has been added.

Planned downtime from 5pm on Friday 3 November to 8am on Monday 6 October 2023 has been added.

Planned downtime from 6pm on Friday 20 October 2023 to 6am Monday 23 October 2023 has been cancelled.

Planned downtime from 6pm on Friday 20 October 2023 to 6am Monday 23 October 2023 has been added.

A service issue about delays in receiving return submission responses when submitting the CT600 form online has been added.

The technical issue effecting Corporation Tax online service has now been resolved.

The Corporation Tax online service is currently unavailable. Check the service availability page for updates.

The service issue about HMRC's free Corporation Tax online return service not showing final submission responses has been resolved.

Planned downtime from 6pm on Friday 14 October 2022 to 6am on Monday 17 October 2022 has been added.

Planned downtime from 6am on Saturday 17 September 2022 to 6am on Monday 19 September 2022 has been added.

Planned downtime from 7:45am to 11am Saturday 13 August 2022 and from 8am to 2pm Saturday 20 August 2022 has been added.

Planned downtime from 8am to midday Monday 1 August 2022 has been added.

Planned downtime from 8am to 6pm on Saturday 16 July 2022 has been added.

Planned downtime from 8am on Saturday 11 June 2022 to 00:01am on Monday 13 June 2022, and 8am on Saturday 18 June 2022 to 00:01am on Monday 20 June 2022 has been added.

Planned downtime from 10am to 2pm on Saturday 4 June 2022 has been added.

Planned downtime from 10am to 2pm Saturday 21 May 2022 has been added.

Scheduled downtime from 8am to 8pm on Sunday 15 May 2022 has been added.

Planned downtime from 8am to 3pm on Saturday 7 May 2022 has been added.

Planned downtime from 8am to 8pm on Sunday 24 April 2022 has been added.

Due to scheduled maintenance you will be unable to access the HMRC free online filing service from Saturday 26 March 2022 7:30am to 8:30am.

A link to guidance on changes and issues that may affect how you use the Corporation Tax online service to file your Company Tax Return has been added.

Planned downtime message for the HMRC free online filing service from 8pm to 11:59pm on Thursday 24 February 2022 has been added.

Planned downtime from 8am to 4pm on Sunday 20 February 2022 has been added.

Planned downtime from 8pm to 9pm on Thursday 10 February 2022 has been added.

Planned downtime from 8pm to midnight on Wednesday 2 February 2022 has been added.

Planned downtime from 8am to 10am Saturday 22 January 2022 has been added.

Planned downtime from 5pm on Friday 3 December 2021 to 9am on Monday 6 December 2021 has been added.

Planned downtime from 5pm on Friday 12 November 2021 to 9am Monday 15 November 2021 has been added.

A service issue about submitting company tax returns due to legislation introduced in the 2021 Spring Budget has been added.

Planned downtime from 5pm on Friday 15 October 2021 to 9am Monday 18 October 2021 has been added.

A service issue about maintenance to the Companies House e-filing system has been added.

Planned downtime from 11:59pm on Monday 4 October 2021 to 12:30am Tuesday 5 October 2021 has been added.

Planned downtime from 12pm to 12:30pm on Tuesday 5 October 2021 has been added.

Planned downtime from 12pm to 8pm on Wednesday 6 October 2021 has been added.

Service issues message explaining that returns filed for accounting periods ending after 31 March 2021 will generate an error has been added.

Planned downtime for the Company Accounts and Tax Online service from 5pm on Friday 6 August 2021 to 9am Monday 9 August 2021 has been added.

Planned downtime from 5pm on Friday 6 August 2021 to 9am Monday 9 August 2021 has been added.

The service issue about Research and Development claims has been resolved.

Planned downtime for the free online filing service from 5pm on Friday 14 May 2021 to 9am Monday 17 May 2021 has been added.

Planned downtime message for the free online filing service from 5pm Friday 16 April 2021 to 9am Monday 19 April 2021 has been added.

Service issue for Research and Development claims added.

Planned downtime from 5pm on Wednesday 24 March 2021 to 9am on Thursday 25 March 2021 has been added.

The planned downtime from 5pm on Friday 19 March 2021 to 9am on Monday 22 March 2021 has been cancelled.

Planned downtime from 5pm on Friday 19 March 2021 to 9am on Monday 22 March 2021 has been added.

Planned downtime from 5pm on Friday 5 March 2021 to 9am Monday 9 March 2021 has been added.

Planned downtime from 8am to 10am on Saturday 20 February 2021 has been added.

Updated planned downtime message for Saturday 13 February 2021 - the free online filing service will be unavailable from 8am to 2pm on Saturday 13 February 2021.

Planned downtime from 8am to 2pm on Saturday 13 February has been added. Companies using the HMRC free filing service (CATO) wishing to joint file or file accounts to Companies House may be affected. HMRC submissions are unaffected and the service will be available during the maintenance period.

Planned downtime from 7pm on Thursday 31 December 2020 to 7am on Friday 1 January 2021 has been added.

The service issues for 'Changes to the Corporation Tax main rate' and 'Annual rate increase for Structures and Buildings Allowance' have been removed.

Guidance has been updated to advise if you need to file your Company Tax Return before July 2020 and need to apply the new rules, contact the Corporation Tax helpline.

The HMRC free filing service (CATO) will be updated for companies that will be, or are already, subject to the off-payroll rules by July 2020.

The HMRC Corporation Tax online service will now be updated for the revised rate of 19% by the last week in June 2020.

The revised rate of 19% should be applied to this service by the second week of July

Service issues updated with information about changes to the Corporation Tax main rate, Structures and Building Allowance annual rate and off-payroll working rules.

Updated to confirm the off-payroll working legislation for the private sector has been deferred until 6 April 2021.

The contact email address for advice about off-payroll working rules has been updated.

The Marginal Rate Relief calculator will be unavailable from 6pm to 8pm on Sunday 16 February 2020. Information about this issue has been added.

The service issues have been updated with information about off-payroll working rules for the private sector.

Planned downtime that was scheduled from 9pm on 25 November 2019 to 6am on 26 November 2019 has been changed. The service will now be unavailable from 9pm on 26 November 2019 to 6am on 27 November 2019.

Information about maintenance for setting up a direct debit between 9pm on Monday 25 November 2019 to 6am on Tuesday 26 November 2019 has been added.

This service will be unavailable from 9pm on Thursday 21 November to 6am on Friday 22 November 2019. Information about this issue has been added.

Planned downtime for 9pm on 12 November 2019 to 6am on 13 November 2019 has been added.

Planned downtime for 9pm on 12 November 2019 until 6am on 13 November 2019 has been cancelled.

Planned downtime from 9pm on 12 November 2019 until 6am on 13 November 2019.

You will be unable to use the 'view liabilities and payments' and the 'view and amend contact details' part of the service from 9pm on Monday 11 November 2019 to 6am on Tuesday 12 November 2019. Information about this has been added.

The service issue 'Companies House filing' has been added.

The service issue about changes that may affect your company tax return has been updated.

The 'Changes that may affect your company tax return' service issue has been updated with more information on submitting a Structures and Buildings Allowance claim online before April 2020.

The service issue about filing to Companies House has been updated.

A service issue about filing to Companies House has been added.

The service issue about filing to Companies House has been removed.

A service issue about filing to Companies House has been added.

A service issue about changes that may affect your company tax return has been added.

The service issue 'Filing using the Companies House system' has been removed.

A service issue about filing using the Companies House system has been added.

The service issue about the temporary increase in Annual Investment Allowance has been resolved.

Information about the service issue for the temporary increase in the Annual Investment Allowance has been amended, to show the Corporation Tax online service will be updated at the end of June 2019.

A service issue about a temporary increase in Annual Investment Allowance has been added.

Downtime previously planned for 17 and 18 November will now take place on 24 and 25 November.

Planned downtime for Wednesday 14 November 2018 9:15pm to 2:45am on Thursday 15 November 2018 has been added.

Service issue for Thursday 8 November 2018 from 6pm to 11pm has been added.

Planned downtime for 3 and 4 November will now take place on 17 and 18 November.

Planned downtime for 3 and 4 November added.

An Issue about submissions on 19 March 2018 and 20 March 2018 has been added to the page.

The service issues section has been updated.

A message about some customers experiencing technical difficulties and delayed submission responses has been added to the page.

Service availability section updated.

The service issues section has been updated.

There is a service availability issue causing delayed submission responses.

A service issue message about HMRC's Corporation Tax free filing software has been added.

The 'Changes that may affect your Company Tax Return - Loss reform' section has been amended with new information about filing your return.

The CT600 Return submission problem has been resolved.

The service issues section has been updated.

CT600 Return submission problem has now been resolved.

The service issues section has been updated.

The service issues section has been updated.

The 'Service issues' section has been updated.

The 'Service issues' section has been updated.

The service issues message about the Corporation Tax online return service - returns with an accounting period ending after 31 March 2017 has been updated as the problem is now resolved.

New message at 'Service issues' added due to online problems with the CATO service.

This guidance has been updated to show latest service issues.

Information regarding HMRC's joint filing service and free filing services for Company Tax Returns has been updated.

Information regarding HMRC's free filing service for company tax returns has been updated.

The routine renewal of Adobe CT600 Trusted certificate section has been updated to reflect the renewal of the embedded certificate.

Spring Budget 2016 content removed

Agents unable to log in to their online account issue updated to show the problem has now been resolved.

The service issues section has been updated to remove the HM Revenue and Customs online filing software - computations trading losses summary page issue.

The 'Agents unable to log in to their online account' message has been updated.

A service issue message has been added to the page.

The Spring Budget 2016: changes that may affect your Company Tax Return section has been updated.

'Error 9316/9965 using HM Revenue and Customs/Adobe return' paragraph added to the page under service issues.

Removal of 'Changes that may affect your Company Tax Return' section.

Service issues section has been updated.

The service issues section has been updated with information about essential maintenance for Companies House online services.

The service issues section has been updated with information from the Spring Budget 2016 about changes that may affect your Company Tax Return.

Important changes to HMRC's free filing service for company tax returns

Service issues section has been updated.

Routine renewal of Adobe CT600 Trusted certificate message added to the page.

Planned downtime has been added to this page.

Downtime for Corporation Tax online service has been added to this page.

Latest updates on creating a new Government Gateway account.

First published.