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Accounts filing deadlines

Private companies and LLPs normally file accounts within nine calendar months of their registered accounting reference date; public companies have six. First accounts and valid shortened periods need additional rules.

Registered dates, calendar months and first accounts

Use the registered accounting reference date (ARD), not the accounts made-up date, which may be up to seven days either side. The default first ARD is the last day of the month containing the first incorporation anniversary. Dormancy can change accounts content, but does not itself change the filing window.

Companies Act 2006 section 443 uses calendar months: a non-month-end date retains the corresponding day, with a missing February day falling at February month-end. A specified month-end date gives a month-end deadline. Thus 4 April 2026 gives 4 January 2027, while 30 April 2026 gives 31 January 2027. Do not use a fixed number of days or JavaScript rollover as the rule.

Incorporation is day one of the first reference period. First periods of 12 months or less use the ordinary nine- or six-month window. If the period exceeds 12 months, section 442(3) uses the later of nine months (private/LLP) or six months (public) after the first incorporation anniversary and three months after the ARD: normally the 21- or 18-month incorporation deadline. The anniversary is a specified date in its own right; preserve its correct month-end status.

An ARD earlier than the normal first reference date implies a changed first period. A correct deadline may require the actual receipt of the valid shortening notice, not just the new ARD. The calculator therefore returns review required if that fact is missing rather than silently assuming the ordinary deadline is final.

For a valid shortening, section 442(4) takes the later of the applicable underlying deadline and three accounts-calendar months from Companies House's actual receipt of AA01. Retain the long-first-period calculation if the shortened first period still exceeds 12 months. The receipt date is not the posting date.

A legally valid lengthening uses the new registered ARD under the applicable first or subsequent rule. It is not the same as a granted filing extension. Normally a reference period cannot be lengthened beyond 18 months, and later lengthenings have frequency restrictions and exceptions. Incorporation counts as day one for the first-period maximum. The calculator does not decide whether a change was legally permitted or validate subsequent period length.

ARD changes must be made before the existing filing deadline; you cannot change an overdue period. A change also removes a filing extension for that period. Check the official register and filing history for the recorded deadline and change facts, rather than treating an entered new ARD as approval of the change.

Rule summary

Standard annual accounts filing windows

Private companies and LLPs normally file annual accounts 9 months after the accounting reference date. Public companies normally file within 6 months.

A month-end registered ARD produces a month-end deadline: 30 April 2026 plus nine accounts-calendar months is 31 January 2027, not 30 January. Non-month-end dates retain the corresponding day, clamped to February month-end where necessary.

First reference periods count incorporation as day one. For periods over 12 months, use the later of nine months (private/LLP) or six months (public) from the first incorporation anniversary and three months from the ARD; normally 21 or 18 months from incorporation. Periods of 12 months or less use the ordinary window.

Section 443 applies month-end handling to specified dates used in accounts filing periods. Generic tax and penalty date arithmetic is unchanged.

For a valid shortened period, section 442(4) selects the later of the applicable underlying deadline and three months from actual receipt of the notice. If the shortened first period still exceeds 12 months, retain the long-first-period rule rather than replacing it with ARD plus nine or six months.

A valid lengthening uses the new registered ARD and the same applicable first/subsequent rule; lengthening is not an approved extension of time to file. Weekends and bank holidays do not extend filing deadlines.

Worked examples

How the rule behaves in practice

  • Corresponding day, not a fixed day count: Later private company accounts with registered ARD 4 April 2026. Deadline 4 January 2027, not 31 January: this ARD is not a month-end date.
  • Later private company accounts: Later private company accounts with registered ARD 30 April 2026. Deadline 31 January 2027: a month-end ARD gives a month-end filing deadline.
  • First accounts with a longer opening period: Private company incorporated 1 January 2025, first ARD 31 January 2026. Later of 1 October 2026 and 30 April 2026: deadline 1 October 2026. This is the Companies House first-accounts example.
  • Shortened first period: receipt-based deadline wins: Private company incorporated 1 January 2025; valid shortened first ARD 31 December 2025; Companies House received the notice on 31 August 2026, before the old 1 October 2026 deadline. Underlying 12-month period deadline: 30 September 2026. Notice receipt plus three accounts-calendar months: 30 November 2026. Select the later date: 30 November 2026. Without the receipt fact, review is required.

Practical consequences

  • Acceptable accounts must reach Companies House by the deadline; posting or submitting rejected accounts is not enough. A weekend or bank holiday does not add time. Apply for any exceptional extension before the deadline and rely on the granted/recorded date, not this calculator's standard result.
  • The ordinary private-company/LLP late-accounts table is £150 up to one month late, £375 over one to three months, £750 over three to six months and £1,500 over six months. Consecutive late financial years can double it; public companies have a different table. Use the dedicated Companies House penalty tool/guide for the supported penalty calculation. Accounts filing is separate from CT600 filing and Corporation Tax payment.
  • UK private companies, public companies and LLPs with accurate registered dates and already-valid changes are the supported cases. Leap-day incorporation, approved extensions, disputed changes, re-registration, overseas entities, insolvency and historic transitional rules need professional review. Dormant-subsidiary exemptions and ARD-change eligibility are not established here.

Important limits

  • Approved filing extensions, disputed changes, leap-day incorporation, first periods over 18 months, overseas companies, re-registration, insolvency and historic transitional cases require review.
  • This is not an ARD-change eligibility check or live register lookup. Subsequent period length/previous ARD and dormant-subsidiary filing exemptions are not established; confirm those facts separately.

Primary sources and review date

Reviewed on . Preserved source review from the accepted scoped statutory repair; this contract migration does not re-date that review.

Applies to: Current Companies Act accounts filing rules, including sections 442–443.

Reviewed scope: Private companies and LLPs; supported first/later accounts and valid changes; extensions and uncertain facts require review.

Review basis and change triggers

Reviewed model: accounts-filing-deadline-calculator: companies-house-accounts-reviewed-28 September 2026

  • A cited source or statutory regime changes.
  • Reviewed content, runtime adapter or domain implementation changes.
  • A new effective period falls outside the supported scope.

Turn the result into an action plan

  • Confirm the registered ARD, entity type and first/subsequent status. For a shortened period, obtain the actual receipt date of the valid change notice; if unknown, verify the official due date instead.
  • Use the calculator's rule explanation and the four worked examples below to check the date. Verify the result against the Companies House register, especially after a change or extension.
  • If the date has passed, read the Companies House late filing penalties guide and use its calculator; do not use a CT600 penalty calculation for accounts.
  • Keep the accounts date alongside confirmation statement and tax dates in the same working calendar.

Use the tool

Accounts Filing Deadline Calculator

Calculate the Companies House deadline for normal, first or valid shortened accounts periods using registered dates and the applicable filing rule.

FAQ

Why does the tool ask for the incorporation date?

It is needed for first accounts because the filing deadline can depend on the incorporation-based statutory deadline as well as the accounting reference date.