Limited company filing deadlines: the full calendar

Private limited companies must file accounts with Companies House within 9 months of their accounting reference date (year end). A late filing penalty applies automatically and escalates the longer the delay runs, doubling if accounts were also late the previous year.

A company's very first accounting period usually runs from incorporation to the accounting reference date chosen by Companies House (the last day of the month of incorporation, one year on), and the first accounts are due 21 months after the date of incorporation rather than 9 months after the year end.

This 21-month window only applies to the first accounts; every subsequent year reverts to the standard 9-month rule from the accounting reference date.

Separately from accounts, a confirmation statement is due within 14 days of the end of each 12-month review period, which runs from incorporation or from the last confirmation statement. It confirms the register (directors, registered office, shareholders, PSCs) rather than any financial information.

Corporation tax must normally be paid electronically within 9 months and 1 day of the end of the accounting period, ahead of the CT600 return deadline. Larger companies paying by quarterly instalments follow a different schedule.

Interest runs from the due date on any tax paid late, regardless of when the return itself is filed.

The CT600, with accounts and computations, is due 12 months after the end of the accounting period, three months after the tax payment deadline. Late filing penalties are £100 immediately after the deadline, a further £100 if still outstanding after 3 months, and then tax-geared penalties of 10% of unpaid tax at 6 months and a further 10% at 12 months.

If the company operates PAYE, payments and Full Payment Submissions run monthly (or quarterly for smaller employers), reported in real time, entirely independent of the company's year end.

VAT-registered companies file and pay according to their own VAT quarter, again unconnected to the accounting reference date, so a company can easily have four different deadline calendars running side by side.

Because each deadline is measured from a different trigger, no single date governs a company's compliance calendar. Changing the year end with form AA01 moves the accounts, corporation tax and CT600 dates, but not the confirmation statement, which runs on its own independent cycle from incorporation.

We handle year-end accounts and corporation tax filings together, so the accounts, CT600 and payment deadlines are managed as one job rather than three (year-end-accounts-and-corporation-tax).

Not sure which deadline applies to you? Use our free filing due date checker (tools/filing-due-date-checker) to see your specific dates.

We are an independent firm of Chartered Accountants, not Companies House or HMRC.

Rates, thresholds and deadlines quoted here reflect the 2026/27 UK tax year. Check current GOV.UK guidance, or ask us, before relying on them for your own company.