Companies House accounts filing deadline calculator

Key facts

As at 25 October 2026.

Work out the deadline

Worked examples

The first three examples are the ones Companies House gives in its guidance on preparing and filing accounts; the fourth applies the rule for a shortened period.

How the calculator decides

• It adds 9 months (private company) or 6 months (public company) to the last day of the period. Whether a company is public or private is judged immediately before the end of the period.
• If you tick the first period and the period is longer than 12 months, it works out both 9 months from the first anniversary of incorporation (21 months in total; 6 and 18 months for a public company) and 3 months after the period ends, and takes the later date.
• If you tick a shortened period, it also works out 3 months from the date of the notice and takes the later of that and the normal deadline.
• It counts months as the Companies Act does: a period ending on 4 April is due on 4 January; one ending on the last day of a month is due on the last day of the target month; a date that does not exist in the target month, such as 30 February, becomes the last day of that month.

Assumptions and limits

• The register comes first. The company's page on the Companies House register shows when the next accounts are due. If it differs from this result, check the dates you entered and any change of accounting reference date.
• Extensions are not included. Companies House may extend the deadline for a special reason if the company applies before it expires; the extended deadline cannot be more than 12 months after the end of the period (Companies Act 2006, s442(5)).
• Delivery means received. Accounts count as delivered when Companies House receives acceptable accounts. Rejected accounts do not stop the clock, so leave time to correct and resubmit.
• Maximum length. An accounting reference period, including an extended one, cannot be longer than 18 months; the calculator refuses a longer period.
• It does not cover overseas companies or the separate deadlines for the Corporation Tax return; use the CT600 deadline calculator for those.

Filing late, and filing from 2028

If the accounts arrive after the deadline, Companies House charges a late filing penalty: for a private company £150 up to one month late, rising to £1,500 after six months, and double that when the previous year's accounts were late too. Work out the amount with the late filing penalty calculator. Late filing is also a criminal offence by the directors.

From 1 April 2028 every company must file its accounts with commercial software, in iXBRL; the web and paper services close for accounts. On 23 October 2026 Companies House confirmed that date and said that small companies may still file abridged or filleted accounts. The deadlines themselves do not change.

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