To create an iXBRL computations file using Ftax you must first complete the main CT600 tax return including the Profits worksheets and any relevent Capital Allowance worksheet:
Make sure you have entered your email address and the accounting period dates on the opening page, and the Company Number and Company Type on the first page of the tax return:
The Company Number should always be 8 digits. Add leading zeros if necessary.
HMRC notes are available to help you choose the correct Company Type. You should also make sure you click the red Calculate Tax button on page 4:
To generate the file, go to the front page of the CT600 and click the iXBRL button at the bottom left of the page:
Select 'iXBRL Computations' and click 'yes' to agree with the popups:
After a few seconds a green success screen should appear:
Click the 'login' button on this screen, login to your Ftax Account on the Ftax website, scroll down to the 'Recent PDF Copies/iXBRL Files' section and click 'Download' to save the file in a known location:
Please note that your Ftax Account home page will only keep copies of the latest versions of your iXBRL Accounts and Computations files.
If a red Error screen is displayed then check you have entered your email address and try again:
If the problem persists then send in a Support Request and attach the saved CT600 to the support ticket:
It is extremely important to always handle iXBRL files with care. Never open an iXBRL file into a browser and then save it as this will corrupt the file.