The normal deadline for filing private limited company accounts is 9 months after the company’s financial year end, known as the accounting reference date. For example, many companies have a year-end date of 31 March and are therefore required to file their accounts by 31 December. For public companies, the time limit is 6 months from the year end.

The deadline for filing your first set of accounts with Companies House can be complicated. If the first set of accounts cover a period of more than 12 months, the filing deadlines are as follows:

• Within 21 months of the date of incorporation for private companies
• Within 18 months of the date of incorporation for public companies
• Or (for either company type) 3 months from the accounting reference date, if this is longer than the above time limits. 

For example, a private company incorporated on 1 January 2019 with an accounting reference date of 31 January, has until midnight on 1 October 2020 (21 months from the date of incorporation) to deliver its accounts.

If the first set of private company accounts cover a period of 12 months or less, then the normal filing deadline applies.

There are automatic late filing penalties if your company accounts are delivered late. The penalties depend on how long has passed from the due date for payment and whether the company is private or public.

After the end of its financial year, a private limited company must prepare full annual accounts and a company tax return. The deadline for filing the first set of accounts with Companies House is 21 months after the date the company was registered with Companies House. Annual accounts must be submitted 9 months after the company’s financial year ends.

There is a fixed date for the payment of Corporation Tax which is 9 months and 1 day after the end of the relevant accounting period. Note that a company is usually required to pay the tax due in advance of the filing deadline for a company tax return.

In most cases a company’s tax return must be submitted within 12 months from the end of their accounting period. Online Corporation Tax filing has been compulsory for company tax returns delivered after 31 March 2011 for accounting periods ending after 31 March 2010. Company tax returns have to be filed using the iXBRL data standard using either HMRC’s own software or third-party commercial software.

The accounting period for Corporation Tax is usually the same 12 month period as the company’s financial year.