Week 53 payroll: what happens to tax and NI

Q: What does that look like in numbers?

Illustration only. A weekly paid employee earns £500 every week. To keep the figures simple, assume their code gives free pay of exactly £240 a week, so £12,480 over 52 weeks, and that all taxable pay falls in the 20% basic rate band. At week 52 the free pay to date is £12,480 and total pay for the year including week 53 is £26,500. Free pay is lower, so tax is due on the week 53 payment. Week 53 tax is worked out on £500 less one week's free pay of £240, so £260 at 20%, which is £52. Across the year the employee has received £12,720 of free pay (53 × £240), which is £240 more than the 52 week allowance. At 20% that is £48 less tax than a strict annual calculation would give. That £48 is the sort of amount HMRC's reconciliation can identify after 5 April. Because it reflects the extra allowance rather than a payroll error, it is the employee's liability.

Q: What mistakes should employers avoid?

Recording a new year payment as week 53. PAYE40060 describes HMRC finding employers who recorded the first payment of a new tax year as a week 53 payment in error. Week 53 belongs only to the old year's final day or days. Changing the code on the final submission. Using the week 1 table for the extra payday does not turn the employee's code into a week 1 code, and CWG2 says the final tax code should not be changed for that reason. Forgetting fortnightly and four weekly payrolls. The same rule applies to a 27th fortnightly or 14th four weekly payday, using the week 2 or week 4 table and tax week 54 or 56. Applying it to monthly pay. There is no month 13. A monthly paid employee's extra payment in March is just part of month 12. Telling the employee the payroll is wrong. A modest underpayment after a week 53 year is an expected result of the rules, not evidence of a mistake. For the other tasks that fall at the end of the tax year, see payroll year end tasks. If HMRC opens a check into your return, tax investigation insurance pays your accountant's fees. Solar Protect cover pays up to £100,000 with no excess; it never pays tax, interest or penalties. Read how our cover works or get a quote.

A week 53 arises when a weekly, fortnightly or four weekly payroll has one more payday in the tax year than usual, because a tax year is 365 or 366 days rather than exactly 52 weeks. On that extra payday the employer taxes the payment on its own, using the week 1 table (week 2 or week 4 for fortnightly and four weekly pay) on a non cumulative basis, so the employee gets an extra period of free pay. That extra allowance is a PAYE convenience rather than a legal entitlement, so HMRC’s check after the year end can show a small underpayment.

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When does a week 53 happen?

Regulation 2 of the Income Tax (PAYE) Regulations 2003 defines a tax week as 6 April to 12 April and each following period of seven days, except that the final tax week, called Week 53, is just the last day of the tax year, or the last two days in a leap year. HMRC’s employer guide CWG2 puts it the same way: the odd day at the end of the year (5 April, or 4 and 5 April in a leap year) is treated as a whole tax week, tax week 53.

An employee therefore has an extra payday only when a regular payday falls on that odd day or days. HMRC’s PAYE Manual at PAYE70015 and CWG2 describe the three versions:

Pay frequency	Usual paydays	Paydays in a week 53 year	Name of the extra payday
Weekly	52	53	Week 53
Fortnightly	26	27	Week 54
Four weekly	13	14	Week 56

Monthly paid staff are not affected. A tax month runs from the 6th of one month to the 5th of the next, so there are always 12 of them.

For 2026 to 2027 the tax year runs from 6 April 2026 to 5 April 2027, and 5 April 2027 is a Monday. An employer whose weekly payday is Monday will therefore have a week 53 payday on 5 April 2027. The next tax year includes 29 February 2028, so its week 53 covers 4 and 5 April 2028, a Tuesday and a Wednesday.

How is PAYE worked out on the week 53 payment?

The rules are in section 1.13 of CWG2 and PAYE70015. For an employee on a normal cumulative suffix code (such as 1257L), compare the total free pay to date at week 52 with the total pay for the year, meaning the week 52 total plus the extra payday:

if the free pay to date is equal to or more than the total pay for the year, deduct no PAYE from the extra payment;
if it is less, work out PAYE on the week 53 pay less the free pay shown in tax tables A for week 1 (week 2 for fortnightly pay, week 4 for four weekly pay), treating that payment on its own.

An employee who is already on a week 1 code is simpler: the extra payday is just another week 1 payment. The payment is reported on the Full Payment Submission with 53, 54 or 56 as the tax week number. CWG2 also says not to change the employee’s final tax code to a week 1 code if the only reason the week 1 table was used is the week 53 calculation. See RTI, the FPS and the EPS for how those submissions work.

What if the employee has a K code?

For a K code, CWG2 section 1.13.2 says the tax is worked out on the week 53, 54 or 56 pay plus the additional pay shown in tax tables A for week 1, week 2 or week 4. The 50% overriding limit on deductions still applies. K tax codes and the 50% overriding limit explains how that limit works.

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Why does the extra payday get extra free pay?

HMRC’s Employment Income Manual at EIM42420 explains the policy. Because certainty of take home pay is important to people planning their finances, the PAYE system allows extra personal allowances on the additional payday, so that net pay in week 53 looks like any other week.

The arithmetic follows from how free pay is built. PAYE70025 says free pay for week 1 is 1/52 of the allowance in the code, week 2 is 2/52, and so on. By week 52 the employee has had the full allowance. Applying the week 1 table again in week 53 gives a further 1/52, so across the year the employee receives 53/52 of the allowance in their code. How cumulative PAYE works period by period shows the free pay calculation in more detail.

How does National Insurance work in week 53?

Class 1 National Insurance for most employees is not cumulative. It is worked out separately for each earnings period, and CWG2 confirms that for weekly pay the earnings period is a week. The National Insurance Manual at NIM08002 explains that earnings periods for regularly paid employees line up with tax weeks, starting on 6 April, and that the odd days at the end of the tax year are treated as a separate week 53.

NIM08010, which refers to regulation 3(2)(b) of the Social Security (Contributions) Regulations 2001, adds that any period left between the end of the last earnings period and the start of the next tax year is treated as an earnings period of normal length. In practice a weekly paid employee’s week 53 pay is compared with the full weekly thresholds, just like any other week. Nothing needs to be clawed back at the year end for National Insurance purposes.

Directors are different. CWG2 and HMRC’s guide CA44 say directors normally have an annual earnings period (or a pro rata annual period), so their contributions are worked out on total earnings for the year and an extra payday simply adds to that total. See National Insurance for company directors.

How is the difference corrected after the year end?

EIM42420 is explicit that the extra allowances given under PAYE do not apply when tax is assessed. Assessments are made on the statutory basis, so a Self Assessment calculation claws back the extra allowance and produces an underpayment. For people who do not file a return, HMRC’s end of year reconciliation compares the tax due on the whole year’s income with the tax deducted.

If that check shows too little tax was paid, HMRC sends a tax calculation letter (P800) or a Simple Assessment letter, between June and March of the following tax year. GOV.UK says an underpayment is usually collected by changing the tax code, in equal instalments over the 12 months from the start of the following tax year, where the person pays tax through an employer or pension provider, earns enough over their Personal Allowance and owes less than £3,000. See P800 tax calculation letters and coding out underpaid tax.

CWG2 anticipates the employee who comes back to the employer with such a letter. If the payroll followed the week 53 rules, the employer should confirm there has been no payroll error and point the employee to the notes sent with the calculation and HMRC’s guidance on tax overpayments and underpayments.

What does that look like in numbers?

Illustration only. A weekly paid employee earns £500 every week. To keep the figures simple, assume their code gives free pay of exactly £240 a week, so £12,480 over 52 weeks, and that all taxable pay falls in the 20% basic rate band.

At week 52 the free pay to date is £12,480 and total pay for the year including week 53 is £26,500. Free pay is lower, so tax is due on the week 53 payment.
Week 53 tax is worked out on £500 less one week’s free pay of £240, so £260 at 20%, which is £52.
Across the year the employee has received £12,720 of free pay (53 × £240), which is £240 more than the 52 week allowance. At 20% that is £48 less tax than a strict annual calculation would give.

That £48 is the sort of amount HMRC’s reconciliation can identify after 5 April. Because it reflects the extra allowance rather than a payroll error, it is the employee’s liability.

What mistakes should employers avoid?

Recording a new year payment as week 53. PAYE40060 describes HMRC finding employers who recorded the first payment of a new tax year as a week 53 payment in error. Week 53 belongs only to the old year’s final day or days.
Changing the code on the final submission. Using the week 1 table for the extra payday does not turn the employee’s code into a week 1 code, and CWG2 says the final tax code should not be changed for that reason.
Forgetting fortnightly and four weekly payrolls. The same rule applies to a 27th fortnightly or 14th four weekly payday, using the week 2 or week 4 table and tax week 54 or 56.
Applying it to monthly pay. There is no month 13. A monthly paid employee’s extra payment in March is just part of month 12.
Telling the employee the payroll is wrong. A modest underpayment after a week 53 year is an expected result of the rules, not evidence of a mistake.

For the other tasks that fall at the end of the tax year, see payroll year end tasks.

If HMRC opens a check into your return, tax investigation insurance pays your accountant’s fees. Solar Protect cover pays up to £100,000 with no excess; it never pays tax, interest or penalties. Read how our cover works or get a quote.

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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.