Filing CT600 After Submitting Accounts Separately

CT600 and Accounts: Separate Filings

If you filed your Companies House accounts through TinyTax and now need to submit your CT600 to HMRC, you start the CT600 as a separate filing — even if you used the same tool for both.

This applies when you:

Chose Accounts only when setting up your filing, or
Filed your accounts first and did not complete the CT600 at the same time

How CT600 and Accounts Work in TinyTax

TinyTax lets you file each obligation separately:

Filing type	Goes to
Accounts	Companies House
CT600 (corporation tax return)	HMRC

When you file Accounts only, TinyTax submits your accounts to Companies House. Your CT600 obligation remains open — it shows as Ready to file on your dashboard and must still be submitted to HMRC separately.

How to File Your CT600 After Accounts

Go to your Dashboard at https://tinytax.co.uk/dashboard and open the company you are filing for
In the filing history, find the CT600 row for the relevant accounting period — it shows as Ready to file
Click File CT600 to begin
Work through the filing form — enter your profit and loss figures and other details
At the preview step, click Submit Corporation Tax and enter your HMRC Government Gateway credentials

HMRC Government Gateway Credentials

At the submission step, you will need:

Field	What to enter
Company UTR	Your 10-digit Corporation Tax reference
Government Gateway ID	Your 12-digit business account ID
Password	Your Gateway account password

⚠ Use your <strong>business</strong> Government Gateway account, not a personal one. If credentials are being rejected, check that Corporation Tax is enrolled on your Gateway at gov.uk/log-in-register-hmrc-online-services.

For help with HMRC login failures or enrolment issues, see: Government Gateway and Corporation Tax Enrolment

CT600 Deadline

Your CT600 must be filed within 12 months of your accounting period end date. The deadline is shown on the dashboard alongside the CT600 obligation row.

Common Questions

I see an "Update Credentials & Retry" button — should I use that?

Only if it appears on a CT600 row in your filing history. If the button appeared alongside an accounts filing (where accounts were submitted but CT600 was not), clicking it will not help you file CT600 — it is linked to the accounts session. Use the File CT600 button on the separate CT600 obligation row instead.

Will I need to re-enter my figures?

Yes — the CT600 filing form holds its own set of figures. Even if you entered P&L figures during your accounts filing, you will need to enter them again when starting the CT600.

Can I file CT600 and accounts in the same session next time?

Yes — when starting a new filing, choose CT600 and Accounts to file both to HMRC and Companies House in one flow.

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