# Any case where MM-DD-YY dating has cost money? **URL:** \ **Category:** Factual Questions\ **Created:** [September 23, 2023, 11:50am UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594 "2023-09-23T11:50:20Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![colinfred](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colinfred/32/21338_2.png) [@colinfred](https://boards.straightdope.com/u/colinfred)\ **Post date:** [September 23, 2023, 11:50am UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/1 "2023-09-23T11:50:20Z")
Americans use MM-DD-YY as a shortform, the rest of the world uses the much more sensible DD-MM-YY. Is there a good example of a case where an American firm in good faith sloppily used MM-DD-YY in their international promotion, and the customers interpreted it as DD-MM-YY, causing the American firm to lose a lot of money due to their offer being much more generous than anticipated and/or having to pay court costs? ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [September 23, 2023, 12:05pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/2 "2023-09-23T12:05:13Z")
Similarly, an obvious source for actual harm leading to litigation would be expiry dates on perishable food or drugs. I just did a spot check, and 100% of food items in my house show the date unambiguously by spelling out the month. But 100% of prescription drug labels (sample size only 4) use the ambiguous numeric date format. ---
**Author:** ![Mighty\_Mouse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mighty_mouse/32/7776_2.png) [@Mighty\_Mouse](https://boards.straightdope.com/u/Mighty_Mouse)\ **Post date:** [September 23, 2023, 12:37pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/3 "2023-09-23T12:37:03Z")
I can testify that companies I have worked for have lost money due to the date format issue. But much more due to Americans not understanding time zones and consequently missing deadlines specified in UTC or Central European Time or Chinese Standard Time or even worse not understanding that 16:30 CET is 4:30pm and not 6:30pm. And these are people with college degrees from well reputed American universities. They just don’t seem to understand that the rest of the world does things differently in many areas. Even after years of decades of working in a global company. Meters vs feet, kilometers vs miles, pounds vs kilograms. Especially in Sustainability measures, we are constantly getting bad data because people cannot figure out that cubic feet to cubic meters is not the same conversion as square feet to square meters. ---
**Author:** ![vbob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vbob/32/4439_2.png) [@vbob](https://boards.straightdope.com/u/vbob)\ **Post date:** [September 23, 2023, 12:47pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/4 "2023-09-23T12:47:08Z")
Time is money. Confusion is lost time. Why oh why can’t we all use some flavor of YYYY-MM-DD? When expressed numerically as part of a designation or file name, it automagically sorts in chronological order! 2023-09-23 or if you want to take the Long View and avoid Y10K problems - [https://longnow.org](https://longnow.org) - 02023-09-23 ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [September 23, 2023, 12:47pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/5 "2023-09-23T12:47:45Z")
Any reasonable business should use CCYYMMDD. DDMMYY is no better than MMDDYY. Both are garbage date formats. CCYYMMDD 2023-09-23 can be sorted and date math is relatively simple. IT Professional. Retired. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [September 23, 2023, 12:51pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/6 "2023-09-23T12:51:01Z")
> [@Mighty\_Mouse](#): > > They just don’t seem to understand that the rest of the world does things differently in many areas. And a lot of people inexplicably cannot grasp what things have some objective foundation that’s _likely_ to be the same everywhere, and what things are obviously completely arbitrary conventions. ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [September 23, 2023, 12:56pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/7 "2023-09-23T12:56:35Z")
> [@colinfred](#): > > the rest of the world uses the much more sensible … ISO 8601 Standard, which is (in long form) " 2023‐09‐23T18:42:53+07:00" and in short form, " 2023‐09‐23" Really, there is no reason to use any other date format. And yes, even amongst my low-level companies in another part of the world, have had shit happen when someone uses US “MM-dd-YYYY” format intead of ISO 8601. Did I mention I am an ISO 8601 fanatic? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [September 23, 2023, 1:03pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/8 "2023-09-23T13:03:56Z")
I made money from date differences. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [September 23, 2023, 1:05pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/9 "2023-09-23T13:05:07Z")
> [@scudsucker](#): > > Did I mention I am an ISO 8601 fanatic? What was the standard before this was introduced on 6th August 2001? ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [September 23, 2023, 1:06pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/10 "2023-09-23T13:06:19Z")
[Complete anarchy, as far as I am aware](https://en.m.wikipedia.org/wiki/ISO_8601#:~:text=It%20unified%20and%20replaced%20a,ISO%203307%2C%20and%20ISO%204031.). ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 23, 2023, 1:35pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/11 "2023-09-23T13:35:42Z")
Personally, I use the format 23 AUG 2023. ISO 8601 can still be misunderstood by an American (and let’s face it, there are a lot of us out there in international commerce), but using letters for the month makes it impossible to interpret any other way, and it also provides a natural divider between the digits. I suppose that 2023 AUG 23 would work just as well, but my format is more familiar to Americans, who are the vast majority of people I interact with. Using abbreviations for the month names does mean that the most trivial sorting routines won’t work on it, but then, any modern spreadsheet will automatically convert dates in any format into whatever format it prefers, and then sort that format correctly, anyway. ---
**Author:** ![Eva\_Luna](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Eva\_Luna](https://boards.straightdope.com/u/Eva_Luna)\ **Post date:** [September 23, 2023, 2:43pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/12 "2023-09-23T14:43:26Z")
Drives me nuts when the IT professionals who designed our crappy immigration forms software cause the forms to populate clients’ birth dates, etc. that way instead of the way they need to because USCIS requires (MMDDYYYY). Which is also not the way most of my clients’ identification documents show it (DDMMYYYY). ---
**Author:** ![Mikkel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikkel/32/13151_2.png) [@Mikkel](https://boards.straightdope.com/u/Mikkel)\ **Post date:** [September 23, 2023, 3:16pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/13 "2023-09-23T15:16:26Z")
> [@Mighty\_Mouse](#): > > …not understanding that 16:30 CET is 4:30pm and not 6:30pm. Don’t your military use a 24 hour clock? As a taxi driver I have often been asked to translate 24 hour times. “I have a meeting at 1300, it’s 12 now, how long time do I have?” ---
**Author:** ![abcdefghij](https://avatars.discourse-cdn.com/v4/letter/a/43a26b/32.png) [@abcdefghij](https://boards.straightdope.com/u/abcdefghij)\ **Post date:** [September 23, 2023, 3:31pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/14 "2023-09-23T15:31:13Z")
ISO 8601 was introduced in 1988, not 2001. It derived from [ISO 2014](https://en.m.wikipedia.org/wiki/ISO_2014), which introduced YYYY-MM-DD in 1976. Before that, yeah, anarchy. ---
**Author:** ![Mighty\_Mouse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mighty_mouse/32/7776_2.png) [@Mighty\_Mouse](https://boards.straightdope.com/u/Mighty_Mouse)\ **Post date:** [September 23, 2023, 3:32pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/15 "2023-09-23T15:32:54Z")
Yes. But the military veterans we have seem to be even less numerate than the rest of the workforce. And even more likely to be hostile to “foreigners” imposing standards on the Free and the Brave. ---
**Author:** ![abcdefghij](https://avatars.discourse-cdn.com/v4/letter/a/43a26b/32.png) [@abcdefghij](https://boards.straightdope.com/u/abcdefghij)\ **Post date:** [September 23, 2023, 3:34pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/16 "2023-09-23T15:34:14Z")
> [@Chronos](#): > > I use the format 23 AUG 2023 Nine years in uniform means I still use this, too, when I sign things. But it doesn’t naturally sort, as others have pointed out about YYYY-MM-DD, so I use the latter for naming logs and data files. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [September 23, 2023, 4:03pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/17 "2023-09-23T16:03:43Z")
> [@abcdefghij](#): > > ISO 8601 was introduced in 1988, not 2001. No, the numerical designation of the ISO always references the date it was introduced, in this case 8/6/01. (I’ll get me coat.) ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [September 23, 2023, 5:05pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/18 "2023-09-23T17:05:43Z")
Not money, but it has cost goodwill. It has caused confusion between anniversaries of Krystallnacht, or the Night of the Breaking Glass, which was November 9 1938, and anniversaries of the attacks on the US on September 11 2001. Krystallnacht sometimes stands for the start of the Holocaust in Europe. It’s what the date “9/11” suggests to most of the world. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [September 23, 2023, 6:28pm UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/19 "2023-09-23T18:28:33Z")
Could be worse. The October Revolution was in November. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [September 24, 2023, 4:56am UTC](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594/20 "2023-09-24T04:56:21Z")
Another strong supporter of ISO 8601 here! I use it wherever I can get away with it. If some specific usage calls for another format, I will use that, but otherwise, it’s ISO 8601 all the way. 🙂 Too many times I have had to enter receipts with dates like “01/02/03” in a country where all the formats are used seemingly at random, and be left guessing what they meant. There has been no reason to use a two-digit year for at least the past thirty years! [Next page](https://boards.straightdope.com/t/any-case-where-mm-dd-yy-dating-has-cost-money/990594.md?page=2)