13 Period Fiscal Calendar 2025. I was trying to adapt the code on the 13 period fiscal calendar (power query m function) to work out with my date periods my im strugling with matching it. Tax periods determine the tax and national insurance thresholds used to calculate your employees' pay.
The tax year spans 2 calendar years, which is why it is commonly referred to by both years. It also lists the week numbers, where week 1 is defined as the week containing the start date of the fiscal year.