Company accounting periods

A UK company has 2 main sets of accounting periods:

  • Those at Companies House, which are determined by Companies Act 2006, and form part of the public record of the company; and
  • Those at HMRC, which are determined by Finance Act 1998, and form the basis of when accounts are sent to HMRC, and when the tax is paid.

The Companies House accounts dates are more flexible, and can affect the dates used for HMRC, so we will look at those first.

Accounting periods at Companies House, and how to change them

Pen on diary in JanuaryA company’s first accounting date is by default set to the last day of the month one year after incorporation. So a company incorporated on 15 June 2014 would have its first accounting date set at 30 June 2015, unless it is changed by the company.

The first accounting period may be changed so that it is any length between 6 and 18 months. This allows any annual accounting date to be adopted regardless of the date of incorporation.

For all accounting periods, the company may choose to file accounts made up to a date within 7 days (before or after) of its registered accounting date. For companies that organise their accounting records weekly, such as bars and restaurants, this allows them to prepare accounts to the same day of the week each year.

At any time before the filing deadline for an accounting period, the company may extend or shorten that accounting period so that it ends on a different date.

In order that the public record of a company’s accounts is regularly updated, an accounting period cannot be extended to longer than 18 months, and in most cases, the accounting period cannot be extended more than once every 5 years. To be more precise, notice cannot be given to extend an accounting period if it is within 5 years of the end of an accounting period that had also been extended.

There are no restrictions on how often an accounting period can be shortened, nor are there any limits on how short a period can be.

All changes to the length of a company’s accounting period need to be registered by a director or the company secretary filing form AA01 at Companies House, or by using their WebFiling online facility. Preparing accounts to a date within 7 days of the current registered date does not require a change in the accounting date to be filed.

Accounts filing deadlines at Companies House

The normal filing deadline for years other than the first year is 9 months after the end of the accounting period. For example, companies with the popular year end date of 31 March are required to file their accounts by 31 December.

Month of March on a calendarThe rules allow for month-end dates, so that a company with an accounting date of 28 February can file its accounts by 31 November, and not 28 November which a strict interpretation of “9 months” might suggest. This will only apply if the company’s accounting date is the last day of the month - a company with an accounting date of 20 January would still have to file its accounts by 20 October, rather than 31 October. Accounts for an accounting period ending on 29 or 30 May would need to be filed by the last day of February.

If the company’s first accounting period is longer than one year, the latest filing date is 21 months from the date of incorporation, or 3 months from the end of the new accounting period, whichever comes later.

If the accounting period is extended to more than one year, and it is not the first accounting period, the latest filing date remains 9 months after the new accounting date.

If the accounting period is shortened to less than one year, the filing date becomes 9 months after the end of the new accounting period, or 3 months after the date the change was made, whichever comes later.

All filing dates given are those by which the accounts must be received by Companies House. It is not enough to post them on the final day, even if proof of posting is obtained.

Filing penalties for late accounts are imposed automatically, and will only be waived in the most exceptional circumstances.

Accounting periods for corporation tax purposes

Corporation tax is charged using its own system of accounting periods, which are often the same as the accounting years used by Companies House, but they can also differ.

A tax accounting period starts as soon as one of the following happens:

  • The company starts trading, or acquires a source of income; or
  • The previous tax accounting period has just ended.

A tax accounting period ends as soon as one of the following happens:

  • At the end of an accounting period at Companies House; or
  • 12 months pass since the start of the period (so a period can never be longer than 12 months); or
  • The company starts trading; or
  • The company stops trading; or
  • The company is wound up.

Corporation tax is payable 9 months and 1 day after the end of the tax period. Accounts are required to be sent to HMRC within 12 months of the end of the tax period.

If accounts are prepared for Companies House which do not match the accounting period required by HMRC, then instead of preparing a second set of accounts for HMRC, the company should apportion the income from its Companies House period to its tax periods, on a daily basis.


A company is incorporated on 1 January 2013, and starts trading on the same day.

It chooses to prepare its first Companies House accounts to 31 March 2014. It must file those accounts at Companies House by 30 September 2014.

The company has 2 HMRC accounting periods:

  1. 1 January 2013 to 31 December 2013, being the maximum length of 12 months, as nothing else has happened to close the period early. This period will comprise 12/15 (approx) of the profits in the Companies House accounts. The tax is payable by 1 October 2014, and the accounts and tax return should be submitted by 31 December 2014.
  2. 1 January 2014 to 31 March 2014, being the period from the end of the previous period, to a Companies House accounts date. This period will comprise 3/15 (approx) of the profits in the Companies House accounts. The tax is payable by 1 January 2015, and the accounts and tax return should be submitted by 31 March 2015.

When is the best year end for my limited company?

There is no single best choice for everyone, but these are the main factors to take into account.

Unless you really want your company accounting year end to coincide with your birthday or wedding anniversary, you will probably choose the last day of a month.

If your business is seasonal, having the year end just before your most profitable period can give you a cash flow advantage in postponing the payment of corporation tax on those profits.

If your priority is to show a strong balance sheet in your company accounts, to assist with raising finance, the company is likely to be in its best financial state shortly after your most profitable period. This would be a good time to draw up your annual balance sheet. For example, for a retailer, this might make 31 December a good choice.

31 December is often convenient, but if there is a lot of company accounting work to be done around the year end, this will need to be fitted in around the Christmas and New Year holidays. This is particularly the case with a year end stock take, which would need to be carried out as near to 31 December as possible.

Month of March on a calendarThe most popular choice is probably 31 March, as it fits in with the income tax, corporation tax and payroll tax years. This can make most tax and accounting matters slightly easier to deal with.

Due to the popularity of 31 March, accountants tend to be busier between June and December each year. You may find that you get a quicker turnaround of your accounts if you choose an accounting date of 30 September or 31 December, and then present your accounting records in either February or March.

The deadline for 31 March accounts is 31 December. If you tend to leave your accounts to the last minute, then you may incur late filing penalties due to delays over the Christmas period.

Corporation tax is payable 9 months after the end of your accounting year, so your choice of accounting date may be influenced by when you want to pay your tax each year. For example, a retailer might instead choose 31 March so they can plan to pay the corporation tax on 31 December using their Christmas takings.

If none of these factors are very important to you, and you just want the simplest option, we would recommend 31 December or 31 March.

12 Comments (oldest first)

  1. Denis Penswick

    I need to decide on finalising my first year accounts. Company was set up in Sept 2013 so automatically I have a 30/09/2014 year end. I understand I can extend up to 31/03/2015.

    I had PAYE earnings in 2013/2014 so only started taking a nominal salary of £660 p/m from April 2014. If I opt for a year end of 30/09/14 I will only have accumulated £3,960 in salary to offset against gross profit and will therefore pay corporation tax on the balance at 20%. If I defer to 31/03/15 I will be able to offset a year’s salary of £7,920 and pay no CT on that sum. Opting for the September year end suggests I will pay £792 in CT that I could avoid by deferring the year end to March 2015. I understand all future salary will reduce the CT liability but opting for Sept 2014 suggests I would be paying HMRC effectively in advance. Am I right?

    3 July 2014

  2. Admin

    You appear to be confusing Companies House accounting periods with corporation tax accounting periods. They are not necessarily the same, the main difference being that a corporation tax accounting period cannot be longer than 12 months.

    3 July 2014

  3. Tom


    My company incorporation date was 29/10/2013 - business started trading on 04/11/2013. Accounting ref date is 31/10/2014

    I am now at the time of submitting my corporation tax returns. I understand I have to submit 2, is the below right?

    1st return from 29/10/2013 - 03/11/2013 (can I submit this as dormant accounts?)
    2nd return from 04/11/2013 - 31/10/2014


    12 November 2014

  4. Admin

    You are basically right.

    For filing accounts at Companies House, you have one set of accounts covering the period 29/10/2013 - 31/10/2014.

    For filing at HMRC, you have a dormant corporation tax return (CT600) for 29/10/2013 - 03/11/2013, with no accounts attached on the grounds that the company was dormant.

    You then have the main corporation tax return for 04/11/2013 - 31/10/2014, with the accounts attached.

    “I am now at the time of submitting my corporation tax returns.”
    Submitting your accounts so soon after the end of the year is very unusual. It raises questions about how accurate the closing balance sheet can be, when you have left so little time for invoices, statements etc to be received and processed. It is like driving in the fog: you cannot see what is ahead.

    13 November 2014

  5. Kayleigh


    I hope you can help. If my company has shortened its year end by a day (i.e. from 30th November 2013 to 29th November 2013) and has filed its accounts with Companies House as at 29th November 2013, what date should be put on the Company Tax return? The accounts prepared and signed are still dated 30th November 2013 but were filed with Companies House as at 29th November as I thought that the 7 day rule would apply as accounts can be filed 7 days either side of the accounting reference date. The accounting reference date is 29th November but I am now confused at to what to do with the Company Tax return. Can it still be dated 30th November given that the accounts are still dated to 30th November 2013?

    Thank you for your help!!

    19 November 2014

  6. Admin

    You can ignore the Companies House Accounting Reference Date. If your accounts have “30 November 2013″ at the top of the page, that is your relevant date for corporation tax purposes.

    19 November 2014

  7. linda

    first company tax return:
    company incorporated on 30/8/2012 and start trading on 30/09/12

    so company house accounting reference date is 31/08/2013.
    1st return is 30/08/12-29/09/12
    2nd return from 30/09/2012 - 31/08/2013

    is that right?

    but why HMRC online service automatically show the accounting filling period is:

    1 January 2015

  8. Admin

    I agree with your corporation tax accounting periods.

    HMRC and Companies House are 2 completely separate government departments, and their computer systems are not well linked. The HMRC system typically does not read the accounting reference date from Companies House, but instead assumes that your next accounting period will be 12 months unless you tell it otherwise. Just file your tax returns with what you think the periods should be, and the HMRC record will correct itself.

    1 January 2015

  9. David

    Hi I have a situation which is:

    Company incorporated 8th March 2013, commenced trading 27th March 2013 and has a first period of accounts ending on 31st March 2014. Accounts submitted to companies house with out a problem. However it appears I have 3 Corporation Tax Return Periods:

    8th March to 26th March 2013
    27th March 2013 to 26th March 2014
    27th March 2014 to 31st March 2014

    Can you unravel this for me or do I submit 3 corporation tax returns for these accounts

    6 January 2015

  10. Admin

    That looks fine to me. You submit 3 returns, the first of which will be inactive.

    7 January 2015

  11. Alan M

    I have a company who incorporated on the 10th May 2013, started trading on the 1st June 2013 and has accounts running to May 31st 2014.

    The question is after arriving at taxable profits of say £23,000 what will be the accounting dates for corporation tax purposes?

    5 February 2015

  12. Admin

    10/05/13 - 31/05/13 : Dormant
    01/06/13 - 31/05/14 : Trading

    5 February 2015