52 or 53 week accounting periods

Q: Why does this suit retailers?

Like for like comparisons. Each year has the same number of each weekday, so weekend trading is not distorted by where the calendar falls. Sales growth figures compare equal numbers of Saturdays. Weekly management cycles. Many retailers plan, pay staff and report in weeks, often in a pattern of four, four and five week periods per quarter. A weekly year end lines the statutory accounts up with the management accounts. A clean cut off. Ending on a Saturday night or Sunday gives a natural point to close tills, count stock and run payroll without splitting a trading week. See cut off at the year end for why this helps the accounts. Group alignment. Section 390(5) requires the directors of a parent company to make sure each subsidiary's financial year coincides with its own unless there are good reasons against it, and a shared weekly pattern makes that easy. The cost is that one year in five or six contains an extra week, which inflates revenue and profit for that year. Users of the accounts need to be told.

Q: What mistakes come up most often?

Drifting outside the seven days. A same weekday policy that is never reset will eventually breach section 390. The 53rd week has to be taken when it falls due. Confusing the year end with the reference date. Changing the reference date needs a section 392 notice; choosing a date within seven days of it does not. Working out the filing deadline from the actual year end. Section 442 counts from the reference date. Assuming HMRC automatically treats a 53 week year as one period. CTM01560 needs a written agreement and a variation of no more than four days. Not flagging the extra week. Turnover in a 53 week year is not comparable with a 52 week year, and lenders and buyers will want to see the effect. Forgetting payroll. Weekly paid staff can have a week 53 in the tax year, which has its own PAYE rules; see week 53 payroll. Solar Protect provides tax investigation insurance for businesses and fee protection schemes for accountancy practices. Read how our cover works or get a quote.

Section 390 of the Companies Act 2006 lets the directors end each financial year on the accounting reference date or on any date up to seven days before or after it. That flexibility is what allows a company to make up accounts to, say, the last Saturday in March every year, giving a 52 week year most years and a 53 week year every so often. Retailers, hospitality groups and other businesses that plan and report in weeks use it so that every year contains whole trading weeks.

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What does section 390 actually allow?

Every company has an accounting reference date. Under section 391 its accounting reference periods run in successive twelve month blocks ending on that date. Section 390 then defines the financial year, which is the period the accounts cover. A subsequent financial year begins the day after the previous financial year ended, and ends with the last day of the next accounting reference period or “such other date, not more than seven days before or after the end of that period, as the directors may determine”.

So the accounting reference date stays fixed, and the directors choose an actual year end inside a fifteen day window around it. Companies House guidance puts it simply: you can make up your accounts to the accounting reference date or a date up to 7 days either side of it. No form is filed to use this flexibility. A change to the accounting reference date itself is a different thing and needs a notice under section 392.

How does a 52 or 53 week year work?

A year of 52 weeks is 364 days, one day short of a calendar year (two in a leap year). If a business always ends its year on the same weekday, the year end drifts back by a day or two each year. Once the drift would take it more than seven days away from the reference date, the business takes a 53 week year instead and the date jumps forward again.

Illustration only. A retailer has an accounting reference date of 31 March and ends its year on the last Saturday in March.

Financial year	Year end (last Saturday in March)	Days from 31 March	Length
2025 to 2026	28 March 2026	3 days before	52 weeks
2026 to 2027	27 March 2027	4 days before	52 weeks
2027 to 2028	25 March 2028	6 days before	52 weeks
2028 to 2029	31 March 2029	On the date	53 weeks

The last Saturday in March can never be more than six days before 31 March, so the rule is always met. A company could equally choose the Saturday nearest to its reference date, which can fall up to three days after it.

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Why does this suit retailers?

Like for like comparisons. Each year has the same number of each weekday, so weekend trading is not distorted by where the calendar falls. Sales growth figures compare equal numbers of Saturdays.
Weekly management cycles. Many retailers plan, pay staff and report in weeks, often in a pattern of four, four and five week periods per quarter. A weekly year end lines the statutory accounts up with the management accounts.
A clean cut off. Ending on a Saturday night or Sunday gives a natural point to close tills, count stock and run payroll without splitting a trading week. See cut off at the year end for why this helps the accounts.
Group alignment. Section 390(5) requires the directors of a parent company to make sure each subsidiary’s financial year coincides with its own unless there are good reasons against it, and a shared weekly pattern makes that easy.

The cost is that one year in five or six contains an extra week, which inflates revenue and profit for that year. Users of the accounts need to be told.

What must the accounts say about a 53 week year?

FRS 102 paragraph 3.10 requires financial statements at least annually. Where the end of the reporting period changes and the accounts cover a period longer or shorter than one year, the entity must disclose that fact, the reason, and that the comparatives are not entirely comparable. Whether or not a 53 week year strictly falls within that paragraph, giving the same three pieces of information is good practice. Many retailers also show the extra week separately in the strategic report or the notes so that underlying growth can be seen.

The heading on the accounts should state the actual dates, for example “for the 53 weeks ended 31 March 2029”. The comparatives are the 52 weeks to 25 March 2028.

Does it change the filing deadline?

No, and this catches people out. Section 442 measures the period for filing from the end of the accounting reference period, not from the date the accounts are made up to: nine months for a private company and six months for a public company. A year end a few days after the reference date therefore leaves a few days less to file. A year end a few days before it gives a little more time.

Illustration only. A private company with a 31 March reference date makes up accounts to Saturday 3 April 2027, the Saturday nearest to 31 March that year. Its filing deadline is still nine months from 31 March 2027, not nine months from 3 April.

How does corporation tax handle a 53 week period?

Under section 10 of the Corporation Tax Act 2009 an accounting period for tax ends at twelve months from its start, at the company’s accounting date, or on certain other events, whichever comes first. HMRC’s Company Taxation Manual at CTM01510 confirms that no accounting period can exceed twelve months. On a strict reading, a 53 week period of account is split into an accounting period of twelve months and a second accounting period of a few days. Our page on accounting periods and periods of account explains the general rules.

HMRC offers a practical alternative at CTM01560. Where a company makes up accounts to slightly varying dates, for example the same Saturday each year, and the year end never varies by more than four days from a mean date, each account may be treated as an account for twelve months to the mean date. The company has to agree to the conditions in writing. If it does not, the rules apply strictly by reference to the statutory accounting periods. HMRC’s own example is a company that draws up accounts to the Saturday nearest 31 December and agrees 31 December as the mean date.

Note the difference in windows: company law allows seven days either side, but the HMRC practice only covers a variation of up to four days. A last Saturday in March policy can be six days from 31 March, so it will not always fit. A Saturday nearest policy does. For what a short period does to rate thresholds, see corporation tax limits for short accounting periods.

What mistakes come up most often?

Drifting outside the seven days. A same weekday policy that is never reset will eventually breach section 390. The 53rd week has to be taken when it falls due.
Confusing the year end with the reference date. Changing the reference date needs a section 392 notice; choosing a date within seven days of it does not.
Working out the filing deadline from the actual year end. Section 442 counts from the reference date.
Assuming HMRC automatically treats a 53 week year as one period. CTM01560 needs a written agreement and a variation of no more than four days.
Not flagging the extra week. Turnover in a 53 week year is not comparable with a 52 week year, and lenders and buyers will want to see the effect.
Forgetting payroll. Weekly paid staff can have a week 53 in the tax year, which has its own PAYE rules; see week 53 payroll.

Solar Protect provides tax investigation insurance for businesses and fee protection schemes for accountancy practices. Read how our cover works or get a quote.

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Sources

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 24 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.