CT600 Filing Checker
Answer a few questions about your company to see whether it has to file a Company Tax Return, and what to do next with HMRC and Companies House.
About the company
HMRC
HMRC has sent a notice to deliver a Company Tax Return, so one is due even though the company is dormant. The return shows no income and no tax.
- File the return online by the deadline on the notice, 12 months after the end of the period. The late filing penalties apply to a nil return too.
- Filing it tells HMRC the company is dormant for that period. You then need no further return unless HMRC sends another notice.
Companies House
- Annual accounts, within nine months of the end of the financial year. These can be dormant accounts if there were no significant transactions in the year.
- A confirmation statement at least once a year.
Example. A limited company that has never traded but has been sent a notice to deliver a Company Tax Return: yes, file a nil CT600. HMRC has sent a notice to deliver a Company Tax Return, so one is due even though the company is dormant. The return shows no income and no tax.
When a company must file a CT600
A company that is active for Corporation Tax files a Company Tax Return for every accounting period, whether it made a profit, a loss or nothing at all. Active means carrying on any business activity: trading, buying or selling, renting out property, employing someone, or receiving income such as bank interest.
A notice to deliver a return
HMRC asks for a return by sending a notice to deliver a Company Tax Return, form CT603. If a company has had one, a return is due for that period even if it was dormant throughout. The return simply shows no income and no tax, and is often called a nil return.
Dormant for Corporation Tax
A company is dormant for Corporation Tax if it has stopped trading and has no other income, or is a new company that has not started any activity. Once HMRC has been told, it stops asking for returns until the company becomes active again.
New companies
A new company has three months from the day it starts any business activity to tell HMRC, by registering for Corporation Tax. A company that is formed and then left untouched has nothing to file with HMRC, but it must still tell HMRC within three months when it does start.
Companies House is separate
Whatever the answer for HMRC, a limited company must file accounts and a confirmation statement at Companies House every year. If it had no significant transactions in the year, the accounts can be dormant accounts.
Frequently asked questions
Does a dormant company need to file a CT600?
Only if HMRC has sent a notice to deliver a Company Tax Return for the period. If it has, a nil return is due. If it has not, and HMRC knows the company is dormant, no return is needed.
Does a company that has never traded need to file a CT600?
No, unless HMRC sends a notice to deliver a return. It must tell HMRC within three months of starting any business activity.
Does bank interest stop a company being dormant?
For Corporation Tax, yes: interest is income, so the company is active and a return is due. Dormant for Corporation Tax and dormant for Companies House are separate tests.
Do I still file with Companies House if no CT600 is needed?
Yes. A limited company files accounts and a confirmation statement at Companies House every year whatever its Corporation Tax position.
Related calculators
Sources: Dormant for Corporation Tax, Company Tax Returns, Set up a limited company: register for Corporation Tax on GOV.UK.
Last updated .
Need to file the CT600?
This calculator is for guidance only. Tax Optimiser prepares the full corporation tax computation and files the CT600 and accounts with HMRC and Companies House.
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