Paper submissions of Corporation Tax Returns, computations and accounts are no longer accepted by HMRC. Accounts, computations and CT600 filings must now be submitted electronically.
At 1 2eFile.com, we offer an integrated E-filing solution which enables you to upload your CT600 (and any supplementary pages), your computations and your accounts and seamlessly converts and bundles them into the required HMRC formats, flagging any errors before final submission.
What You Must File:
To make a valid electronic Corporation Tax return, you need to submit all three of the following simultaneously:
- Annual Accounts in iXBRL format
- Computation of the Accounts in iXBRL format
- CT600 (and supplements) in HMRC XML format
(or CSV that can be converted to XML)
We provide iXBRL tagging services for your accounts or computations. We also provide the XML conversion for CT600 / supplements (from CSV) so you don’t have to generate the XML yourself. If you need help generating iXBRL-tagged accounts or computations, you’ll need to use compatible software or a third-party tagging service.
We also support:
- Late / past year submissions
- Amended account or tax return submissions
- Partner / API integrations, subject to mutual agreement
How it works?
- You upload the three required components (CT600 + supplements, computations, accounts).
- We convert the CT600 from CSV (if needed) into HMRC’s XML format.
- We validate all three documents against HMRC’s business rules and check for errors in real time.
- You’ll receive immediate alerts if there are issues, with pointers to where corrections are needed.
- Once everything passes validation, you can preview the combined return (CT + accounts) in PDF form.
- After your final review, click ‘Submit’ to send the complete package via HMRC’s XML submission protocol.
- On successful submission, you receive a proof of E-filing certificate showing timestamp, what you filed, HMRC markers, etc.