HMRC's free CT600 filing service has closed: what small companies use now
Updated · Rotomal
HMRC closed its free service for filing company accounts and the CT600 together on 31 March 2026. Corporation Tax returns now have to be filed with commercial software that HMRC recognises, or by an agent using it. Companies House WebFiling still accepts accounts until 1 April 2028, so the accounts part can stay free until then; the CT600 cannot.
What closed, and when
The service many small companies used to file accounts and the Company Tax Return (CT600) in one go, often called CATO, closed on 31 March 2026. From then on, HMRC expects Corporation Tax returns to be filed with commercial software. Returns that are due are still due: the closure did not move any deadline.
What is still free
- Companies House WebFiling for accounts, until 1 April 2028. Accounts filed on or after that date must go through software.
- HMRC's list of recognised Corporation Tax software, on gov.uk, which shows products and their prices; some suppliers offer free tiers with limits.
- Your Corporation Tax online account, for paying and viewing records.
Your options now
| Option | Typical cost | Fits |
|---|---|---|
| Accountant | £150–400+ a year for a dormant company | Anything unusual: director's loans, R&D, property disposals, groups |
| Recognised low-cost CT600 software | From about £20 a year (dormant) excluding VAT | Simple and dormant companies happy to fill in the return themselves |
| Practice desktop suites | £100–300+ a year | Accountants with many clients |
| Plain Filings (early access) | £29–49 a year including VAT | Dormant and one-person companies; files prepared for you to submit until our recognition completes |
Deadlines that did not change
- Company Tax Return (CT600): 12 months after the end of the accounting period.
- Corporation Tax payment: 9 months and 1 day after the end of the accounting period, for most small companies.
- Companies House accounts: 9 months after the year end (21 months after incorporation for the first accounts).
Late-filing penalties went up
For Corporation Tax returns due on or after 1 April 2026, HMRC's late-filing penalties doubled: £200 if the return is late and £400 if it is more than three months late. Companies House late-filing penalties for a private company start at £150 and double if the accounts were also late the previous year.
Dormant companies
A dormant company only has to file a CT600 if HMRC has sent a notice to deliver a Company Tax Return. It still files dormant accounts with Companies House every year, which WebFiling accepts until April 2028.
Questions
Can I still file a CT600 for free?
Not through HMRC's own service, which closed on 31 March 2026. Some recognised software suppliers offer free or very cheap tiers with limits; check HMRC's software list on gov.uk.
Do I need to download my old returns?
Keep copies of past returns and computations for your records; companies must keep records for six years. Your Corporation Tax online account and your own files are the places to look.
Sources
- GOV.UK: closure of the service to file your company accounts and tax return Source: gov.uk
- GOV.UK: increases to Corporation Tax late filing penalties Source: gov.uk
- GOV.UK: Company Tax Returns Source: gov.uk
- GOV.UK: Companies House late filing penalties Source: gov.uk
- Changes to UK company law: changes to accounts Source: changestoukcompanylaw.campaign.gov.uk