Re: Week Numbers for Tax Year

See inline comments...

Some more information:

This week number routine is required for an Excel invoice *** that I use. I always use ISO week numbers on my invoices (this week is ISO week 23).

Once we figure out what to give you as a Tax Week Number (see other comments as there are still questions remaining), are you also going to need a translation of that Tax Week Number to the ISO Week Number?

My main client says they use Tax Year week numbers, but it seems that their system assumes that the week with 1 April in it (ISO week number 13) is Tax Year week 1. This week (ISO week number 23) would then become my client's Tax Year week number 11.

As Roger points out in his response to this same message I am responding to, ISO Week Number 1 does not have to include January 1st in it depending on whether the week with January 1st contains a Thursday or not, so I am not so sure that April 1st will always land in ISO Week Number 13. And the "Thursday Rule" for ISO week numbering would make a constant relation to your client's Tax Week Number calculation out of the question as, if your statement is correct, the day April 1st falls on is unimportant in determining your client's Tax Week Number... Tax Week Number 1 is whatever week contains April 1st. Of course, using this definition completely ignores the IR April 6th rule for the start of the Tax Year's weekly numbering.

If we accept that the week with 6 April 2007 in it (2 - 8 April, ISO week number 14) is the first week of the new Tax Year, then this week (ISO week number 23) must be Tax Year week number 10.

However, (according to Sage) it seems that the week with 6 April 2007 in it is considered to be the last week of the old 2006-07 Tax Year, and ISO week number 15 (9 - 15 April) is the first week of the new 2007-08 tax year. This week (ISO week number 23) then becomes Tax Year week number 9.

I think, when looking for the last week of the Tax Year, you need to look at April 5th, not April 6th as they may not both occur within the same weekly time period.

I suppose it doesn't help that ISO week numbers run from Monday to Sunday, whilst Tax Year week numbers appear to run from Friday to Thursday (if Tax week 10 commences on Friday, 08 Jun 2007, as stated above).

The "real" Tax Week Number day-to-day-runs change yearly... the "real" Tax Week Number 1 always starts on April 6th (no matter what day of the week that is) and ends on April 12th, the "real" Tax Week Number 2 always starts on April 13th and ends on April 19th, etc.

Alright, so I am confused now.<g> Can you spell out what criteria you want to govern when Tax Week 1 occurs (in general, not for just this year)? It looks like you (well, I should say you client) wants it to be the full calendar week that contains April 1st (not April 6th)... is that correct? What does your client consider a calendar week... Sunday to Saturday or Monday to Sunday? Does the ISO Thursday Rule factor into the week numbering when using the April 1st Rule that your client appears to use?

Rick

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