Background information

Week numbers annoy me – where did this nonsense come from anyway?

25/11/2023

Translation: Jessica Johnson-Ferguson

It seems anyone who’s anyone in business has to think in calendar weeks. Well, I can’t. What’s the point of this bizarre way of counting?

I recently wanted to find out when the carpenter was coming round to make a small adjustment to our front door. «Calender week such and such,» was the reply. I remained silent on the other end of the line. What should I have said? Is that in the far future or really soon? I don’t live by calendar weeks, but by weekdays. I think in months and find the concept of seasons quite useful. There’s also this nifty little invention of numbering the days of the months from one to about 30.

Why on earth would you need week numbers as well? Couldn’t the carpenter just have told me that he’d be there in the week of 20 November? That would’ve been precise enough. The fact that this also happens to be calendar week 47 is all the better!

But seriously, someone must’ve come up with week numbers at some point and fallen in love with the idea. From the mid-1970s onwards, the idea became roughly official, with the German Industrial Standard (DIN) 1355-1 coming into force in March 1975. This is the first document confirming the existence of the «calender week». It was defined that a calendar week or should have seven days. Sure, it always did, but this time, it was officially standardised.

ISO standard closes DIN gaps

Speaking of standards. When it comes to calendar weeks, things didn’t stop at DIN 1355-1. A few decades later, the International Organisation for Standardisation, or ISO for short, came onto the scene. Its work on the subject of calendars is called ISO 8601 and was first published in 1988 and last updated in 2019. The ISO standard closed the gaps left by the DIN standard. For example, that the first day of a calendar week is always a Monday – at least in German-speaking countries. And, much more importantly for daily business and heavy users of the calendar week, it determines which week of the year calendar week 1 is. This is how:

The first calendar week of the year is the week that’s the first to have a Thursday in it. This means that 4 January is always in the first calendar week. This rule prevents the first working week from not containing a single working day.

Chew on that for a minute. People working in standardisation offices have actually thought about these things. And all of this so some hotshots can boost their egos by telling me we can discuss the matter briefly in calendar week 50 on Wednesday from 1:30 to 1:45 p.m. All other slots in their tightly packed calendar weeks were already taken. Probably by meetings to discuss «Q1 results».

Calendar with calendar weeks

What calendar type are you?

The «calendar week» concept is great – I use it every day.
39%
Calendar week, you say? I need to google that every blasted time.
55%
I don't need a calendar. I'm as free as a bird.
6%

The competition has ended.

If you’re the calendar week type, I’ve a fine selection of calendars for you that will satisfy your passion for this type of time management.

Calendars

Biella Planning annuel mural

68 x 98 cm, No binding, German, French, Italian, English

Calendars

Biella Desktop Delta

12.5 x 15.5 cm, No binding, German, Italian, English

Agenda

Moleskine Weekly

13 x 21 cm, English

Calendars

Biella Planning annuel mural

68 x 98 cm, No binding, German, French, Italian, English

Calendars

Biella Desktop Delta

12.5 x 15.5 cm, No binding, German, Italian, English

Agenda

Moleskine Weekly

13 x 21 cm, English

Header image: Martin Jungfer

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Martin Jungfer

Head of Content

Martin.Jungfer@digitecgalaxus.ch

Journalist since 1997. Stopovers in Franconia (or the Franken region), Lake Constance, Obwalden, Nidwalden and Zurich. Father since 2014. Expert in editorial organisation and motivation. Focus on sustainability, home office tools, beautiful things for the home, creative toys and sports equipment.

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