Help Centre · Corporation Tax · 4 min read

CT600 declaration date: when it differs from the accounts approval date

Declaring the CT600 on a different day from the accounts approval? How to put the right date in box 980 without changing the approval date in the accounts.

The directors approve the accounts on one day; the Company Tax Return is often declared on another. A common case: the accounts were approved and filed at Companies House in September, and the CT600 is prepared and declared in October. Tax Optimiser keeps the two dates apart, so you can put the right date in box 980 of the CT600 without touching the approval date printed in the accounts.

Two dates, two jobs

  • Directors’ signage date — the date the board approved the accounts. It is printed on the balance sheet and tagged in the accounts sent to Companies House and to HMRC. It is required before anything can be filed.
  • CT600 declaration date (optional) — the date the person named in box 975 declares that the return is correct and complete. It appears only in box 980 of the CT600.

Both are on the General tab of the Corporation Tax computation. If you leave the declaration date blank, box 980 shows the signage date, which is right whenever the accounts and the return are approved on the same day.

When to enter a separate declaration date

Enter one when the return is declared on a different day from the accounts approval — for example when:

  • the accounts are already filed at Companies House and the CT600 follows later;
  • the directors signed the accounts some time ago and the computation has only now been finished;
  • you are sending an amended return and want box 980 to show the date of the new declaration.

Heads up — don’t change the Directors’ signage date to the day you declare the return. The accounts attached to the CT600 are generated from the period when you submit, so HMRC would receive accounts with a different approval date from the set at Companies House.

Set the declaration date

  1. Open the period and choose Corp Tax Calculations.
  2. On the General tab, find the declaration rows: Director accepting (box 975), Directors’ signage date and CT600 declaration date (optional) (box 980).
  3. Leave the signage date as the date the accounts were approved.
  4. Enter the day the return is being declared in CT600 declaration date, then click Save.
The General tab with Directors' signage date 16/09/2026 and CT600 declaration date 04/10/2026

The declaration date should not be earlier than the signage date — the return relies on the approved accounts — and the screen warns you if it is. To go back to using one date for both, clear the field and save.

Check box 980 and the accounts

Still in the computation, open CT600 Boxes and scroll to the Declaration group. Box 980 now shows the declaration date.

The CT600 Boxes section with box 980 Declaration date showing 04/10/2026

The CT600 PDF carries the same date on its declaration page. (The copy is watermarked as a draft until the return has been sent.)

The declaration on the CT600 PDF: box 975 Sam Carter, box 980 04 10 2026, box 985 Director

The accounts are untouched. In View Accounts, the balance sheet still says the accounts were approved on the signage date.

The statement of financial position, approved by the board of directors on 16 September 2026

What HMRC receives

The online return contains the declaration itself — the confirmation that the return is correct and complete, with the name and status of the person making it (boxes 975 and 985). HMRC’s online format has no field for the declaration date, so box 980 is not transmitted; HMRC records the date it receives the return. Box 980 appears on the CT600 PDF you keep and give to your client, which is why it is worth getting right.

Nothing is sent to Companies House when you file the CT600, and changing the declaration date never alters accounts that have already been filed there. When you are ready, send the return as usual: see Submitting to HMRC and Companies House.

Common questions

Does submitting the return set the declaration date automatically?

No. Box 980 shows the CT600 declaration date if you entered one, and the Directors’ signage date otherwise. Submitting does not change either.

Do I have to enter a declaration date?

No, it is optional. Leave it blank when the return is declared on the day the accounts were approved.

Will entering a declaration date change the accounts or mean filing them again?

No. It affects only box 980 of the CT600. The approval date in the accounts stays as the Directors’ signage date, and nothing is re-sent to Companies House.

The period is longer than 12 months and has two returns. Which one does the date apply to?

Both. The two CT600s for a long period of account share the same declaration name, date and status.

Can I change the date after the return has been sent?

The field is locked with the rest of the computation once the period is locked. If you send an amended return, unlock the period, update the date and save before submitting again.

The short version

CT600 declaration date: when it differs from the accounts approval date — in brief

The Directors' signage date is the date the accounts were approved. It is printed in the accounts and, by default, in CT600 box 980.

When the return is declared on a different day, enter that day in CT600 declaration date (optional) on the General tab of the computation. Only box 980 changes.

Don't move the signage date to the declaration day: the accounts sent to HMRC would then show a different approval date from the set at Companies House.

HMRC's online return carries the declaration name and status but no date, so box 980 appears only on the CT600 PDF.