Key facts
- HMRC divides the tax year into 12 tax months (6th to 5th) and 53 tax weeks.
- Each FPS must report the correct tax period and payment date.
- Weekly payroll follows tax weeks 1–53; monthly payroll follows tax months 1–12.
- Four-weekly payroll produces 13 pay periods per year, not 12.
- Misaligned pay periods can cause incorrect tax calculations and HMRC queries.
Why Pay Period Alignment Matters
HMRC divides the tax year (6 April to 5 April) into tax weeks and tax months. Every FPS submission must report the correct tax period for each payment. If the period is wrong, HMRC’s records will not match your payroll, potentially causing incorrect tax code adjustments, unexpected payment demands, or penalties.[1]
Tax Weeks
The tax year has 52 complete weeks (occasionally 53):[2]
| Tax Week | Dates |
|---|---|
| Week 1 | 6 Apr – 12 Apr |
| Week 2 | 13 Apr – 19 Apr |
| Week 13 | 29 Jun – 5 Jul |
| Week 26 | 28 Sep – 4 Oct |
| Week 39 | 28 Dec – 3 Jan |
| Week 52 | 22 Mar – 28 Mar |
| Week 53* | 29 Mar – 5 Apr (if applicable) |
*Week 53 only applies to weekly and fortnightly payrolls when the pay day falls in the final days of the tax year.
Tax Months
Tax months are used for monthly payrolls and for calculating PAYE payment deadlines:
| Tax Month | Period | PAYE Payment Due (Electronic) |
|---|---|---|
| Month 1 | 6 Apr – 5 May | 22 June |
| Month 2 | 6 May – 5 Jun | 22 July |
| Month 3 | 6 Jun – 5 Jul | 22 August |
| Month 4 | 6 Jul – 5 Aug | 22 September |
| Month 5 | 6 Aug – 5 Sep | 22 October |
| Month 6 | 6 Sep – 5 Oct | 22 November |
| Month 7 | 6 Oct – 5 Nov | 22 December |
| Month 8 | 6 Nov – 5 Dec | 22 January |
| Month 9 | 6 Dec – 5 Jan | 22 February |
| Month 10 | 6 Jan – 5 Feb | 22 March |
| Month 11 | 6 Feb – 5 Mar | 22 April |
| Month 12 | 6 Mar – 5 Apr | 22 May |
Matching Pay Frequencies to Tax Periods
| Pay Frequency | Pay Periods per Year | Tax Period Used | Notes |
|---|---|---|---|
| Weekly | 52 (or 53) | Tax week number | Matched by payment date to the correct tax week |
| Fortnightly | 26 (or 27) | Tax week number | Each fortnightly period spans 2 tax weeks; use the week of the payment date |
| Four-weekly | 13 | Tax week number | One tax month will contain 2 pay days in some months |
| Monthly | 12 | Tax month number | Aligned with HMRC tax months (6th to 5th) |
Common issue with monthly payrolls: If you pay employees on the last working day of the calendar month, the payment date may sometimes fall before the 6th (in the previous tax month) or after it. For example, paying on 31 May falls in tax month 2 (6 May – 5 June), but paying on 5 May falls in tax month 1 (6 April – 5 May). Your payroll software should handle this correctly based on the actual payment date.
Special Considerations: Four-Weekly Payroll
Four-weekly payroll can cause confusion because 13 pay periods do not divide evenly into 12 tax months. One tax month each year will contain two paydays. This means:
- Your PAYE payment for that month will be roughly double the normal amount
- Employee tax deductions are calculated correctly by the software on a per-period basis
- Budget for the “double month” in your cash flow planning
Tip: Your payroll software automatically assigns the correct tax period based on the payment date. The most important thing is to enter the actual date the employees are paid, not the date you process the payroll. Getting the payment date right ensures correct tax period alignment.
Frequently Asked Questions
What is a tax week?
A tax week is a 7-day period starting from 6 April. Tax week 1 runs from 6 April to 12 April, tax week 2 from 13 April to 19 April, and so on. There are 52 complete tax weeks, plus a short week 53 at the end of the tax year (which only applies if the payday falls on 5 April or in the days leading up to it, depending on the pay cycle).
What is a tax month?
A tax month runs from the 6th of one calendar month to the 5th of the next. Tax month 1 is 6 April to 5 May, tax month 2 is 6 May to 5 June, and so on through to tax month 12 (6 March to 5 April). PAYE payments to HMRC are due based on tax months.
How does four-weekly payroll work with tax periods?
Four-weekly payroll produces 13 pay periods per year. Each pay period aligns with the tax week of the payment date. Your payroll software handles this automatically, but be aware that one tax month will contain two pay periods, which means a higher PAYE payment to HMRC that month.
What is tax week 53?
Tax week 53 is a short additional week that occurs in some tax years when the pay day falls after tax week 52 but before 6 April. It mainly affects weekly payrolls. In week 53, employees receive a pro-rated tax-free allowance for the extra period, which means slightly less tax than normal. Most payroll software handles this automatically.
Further Reading
- Full Payment Submission (FPS) — what each FPS must contain
- Real Time Information (RTI) Overview — the full RTI system
- Key Payroll Dates Calendar — all important payroll deadlines for the year
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Sources
- Running payroll — GOV.UK
- What payroll information to report to HMRC — GOV.UK
- Rates and thresholds for employers 2026 to 2027 — GOV.UK