In every left to right language, the largest value numerical digits are on the left, smallest value digits are on the right.
The country doesn't matter. Years are bigger than months. Months are bigger than days. If your country does anything other than YYYY*MM*DD, they're doing numbers wrong.
That's a stretch. You start with bigger unit first, then switch to biggest last. The only way I would accept this is all units ordered the same way, so You either start with years but that won't fit or you start with minutes, but that would be insane and also not fit. And why do You skip seconds?
The sane ordering outside iso8601 revolves around the most significant bit. When you ask for the time, 34 minutes is usually not significant in any matter in written contexts since you could be reading it more than an hour later. Hence hours are more significant than minutes (verbal can often be an exception, "20 minutes past" can be enough context if someone asks for the time). But the "time" part of datetime is always more significant than the "date" part. The year is least significant since that one changes the least, then comes month, and lastly year. In many contexts knowing it is 14th of September is enough. In chats it might even be enough to say "14th" if you're talking about a date in this very month. But due to the timespan between writing and reading, minutes more often than not is meaningless without hours, hence hours become more significant.
Of course HH:mm dd/mm/yyyy is inferior when it comes to computer parsing due to iso8601 being the easiest to sort. (And because of Americans it is the only format to cause no confusion). But it is going least significant first in the sense that you are presented with year first, something that is often redundant in human-to-human interaction (depending on context you might say year is more significant than time in the case of wanting to know when an article was released, but you know, there's always more exceptions than rules).
So to sum it up: Use whatever date time format you want as long as you use a format fit for the context it is used in. Unless you're saving it to a database/directory/etc. Then use iso8601 so I can easily sort it.
You're using the word "significant" in a colloquial/informal way, but in terms of the strict mathematical definition, most significant digits to least significant is about the size of the unit. If you were to create a dial system, the most significant digits move the slowest and the least significant digits move the fastest.
Or, if you are rounding a measurement to the N most significant figures, you are by definition keeping the largest units and rounding off the rest.
So ISO 8601 properly orders it left to right, largest to smallest, without exceptions. It can be truncated for lower precision, like how 2026-09-14T20:15:35 takes place in a particular year (2026), or a particular calendar month (2026-09) or a particular day (2026-09-14).
Yeah, significant bit in my explanation shouldn't be confused for endianness, that works like you explained. But I'm still of the opinion that iso8601 is best saved for when you need to save dates/datetimes or when confusion can occur. Human-to-human communication is more often than not informal and redundant information can be left out more often and that is where the significance of the bits comes in. Maybe I should have called it the importance of the parts to avoid confusion.
But save to say, I use iso8601 most often anyway. Who is communicating with other humans nowadays?
Yeah... People are weird in this comment section. One person said the only natural way to read numbers was biggest first, as if it were a universal truth. And while there are variations in date format, to my knowledge most people don't write the date with the year first? Like, it's the least useful number to put first. I have rarely asked for the date and been actually inquiring what year it is. The day is the number I want to know most of the time. Day, month, year, in order of which number you most likely need to know first.
Month, day, year on government forms for some reason, though :/
The day is the number I want to know most of the time. Day, month, year, in order of which number you most likely need to know first.
No, getting the year wrong by 1 is much more significant than getting the day wrong by 1. If you're arguing that it won't happen because people will infer from context the correct year, then you're actually assuming that the person already does know the year first. The only reason why people don't state the year is because it is already known by the listener. But just because it's unstated doesn't mean that it isn't critically important.
If you're measuring duration, for example, you will put the largest unit first. The longest serving prime minister of the UK served for 20 years and 315 days. Magellan's expedition around the lasted 2 years, 11 months, and 16 days, if you count from Sanlúcar de Barrameda. The course record for the Iditarod race is 7 days, 14 hours, 8 minutes, and 57 seconds.
And some languages are more irregular than others about numbers. In English, we say "sixteen" where the ones digit is said before the tens digit. French has some base 20 naming conventions that screw up the order, too.
But when we write numbers, we go left to right, largest to smallest. That's why describing time should follow the same convention, and why ISO 8601 exists.
44 replies
Call me when it's the calendar notarisation the rest of the world uses, only 3 continues use your fucked up backwards way of doing it
I refuse to accept date/time formats that don't sort automatically. yyyy-MM-dd or bust
See you in 89 years
≈
Gonna get up at 3:14 and eat a whole pie then go back to sleep
Just like every day
τ/2
This is part of the Pi Expanded Universe.
American calendar notation only.
Day month year is about as universally a standard as metric. USA is month day year.
People complaining about the time and date format, and not the equal sign for an approximation...
That's 03:14 if it's HH/MM, you absolute heathen.
03.1415926
man printf
Sorry, next year...next digit is 5 so need to round up.
Any intelligent person uses MM:HH 😤
Well, you can celebrate it with us inbreeds then.
The date is backwards. 2026-09-15
Well yes, but this will never exist in ISO 8601, sadly. We'll take what we can get, see you in 3141!
#iso8601ultras!
Not on Germany.
It's backwards everywhere
Backwards as in yyyy-mm-dd?
Yeah, no.
https://en.wikipedia.org/wiki/List_of_date_formats_by_country
In every left to right language, the largest value numerical digits are on the left, smallest value digits are on the right.
The country doesn't matter. Years are bigger than months. Months are bigger than days. If your country does anything other than YYYY*MM*DD, they're doing numbers wrong.
I'm glad you get to definite wrong for everyone else
Also I got news for you
There are a variety of formats that are thriving and in constant use all over the world that differ from what you consider correct
(I've never encountered a date format nazi before, this is first contact for me.)
I guess you haven’t had the pleasure of working with many database administrators then ;)
Human readable: Either ddmmyyyy or yyyymmdd
Computer: yyyymmddhhmmss only.
Imo the only wrong thing to do is mmddyyyy
That 's just cursed. Like imperial system.
It's not the boon it seems to be.
I'm aware. That's why it's annoying to be the one who determines right and wrong, nobody listens.
LOL
The world might just end.
Happy Pi Day Eve, everyone!!!
03:14 15/09/2026
So broken.
2026-09-15T03:14:00Z
RFC3339 or RFC9557 or bust.
Well, that's not a circle at all. I'm beginning to think Pi Day is something made up to sell protractors in stores to unknowing kids.
Imma celebrate in the pm.
14:03
That's a stretch. You start with bigger unit first, then switch to biggest last. The only way I would accept this is all units ordered the same way, so You either start with years but that won't fit or you start with minutes, but that would be insane and also not fit. And why do You skip seconds?
The sane ordering outside iso8601 revolves around the most significant bit. When you ask for the time, 34 minutes is usually not significant in any matter in written contexts since you could be reading it more than an hour later. Hence hours are more significant than minutes (verbal can often be an exception, "20 minutes past" can be enough context if someone asks for the time). But the "time" part of datetime is always more significant than the "date" part. The year is least significant since that one changes the least, then comes month, and lastly year. In many contexts knowing it is 14th of September is enough. In chats it might even be enough to say "14th" if you're talking about a date in this very month. But due to the timespan between writing and reading, minutes more often than not is meaningless without hours, hence hours become more significant.
Of course HH:mm dd/mm/yyyy is inferior when it comes to computer parsing due to iso8601 being the easiest to sort. (And because of Americans it is the only format to cause no confusion). But it is going least significant first in the sense that you are presented with year first, something that is often redundant in human-to-human interaction (depending on context you might say year is more significant than time in the case of wanting to know when an article was released, but you know, there's always more exceptions than rules).
So to sum it up: Use whatever date time format you want as long as you use a format fit for the context it is used in. Unless you're saving it to a database/directory/etc. Then use iso8601 so I can easily sort it.
You're using the word "significant" in a colloquial/informal way, but in terms of the strict mathematical definition, most significant digits to least significant is about the size of the unit. If you were to create a dial system, the most significant digits move the slowest and the least significant digits move the fastest.
Or, if you are rounding a measurement to the N most significant figures, you are by definition keeping the largest units and rounding off the rest.
So ISO 8601 properly orders it left to right, largest to smallest, without exceptions. It can be truncated for lower precision, like how 2026-09-14T20:15:35 takes place in a particular year (2026), or a particular calendar month (2026-09) or a particular day (2026-09-14).
It's the best format and everyone should use it.
Yeah, significant bit in my explanation shouldn't be confused for endianness, that works like you explained. But I'm still of the opinion that iso8601 is best saved for when you need to save dates/datetimes or when confusion can occur. Human-to-human communication is more often than not informal and redundant information can be left out more often and that is where the significance of the bits comes in. Maybe I should have called it the importance of the parts to avoid confusion.
But save to say, I use iso8601 most often anyway. Who is communicating with other humans nowadays?
Is this supposed to be a joke? Because this is the standard datetime format in large parts of the world
Yeah... People are weird in this comment section. One person said the only natural way to read numbers was biggest first, as if it were a universal truth. And while there are variations in date format, to my knowledge most people don't write the date with the year first? Like, it's the least useful number to put first. I have rarely asked for the date and been actually inquiring what year it is. The day is the number I want to know most of the time. Day, month, year, in order of which number you most likely need to know first.
Month, day, year on government forms for some reason, though :/
No, getting the year wrong by 1 is much more significant than getting the day wrong by 1. If you're arguing that it won't happen because people will infer from context the correct year, then you're actually assuming that the person already does know the year first. The only reason why people don't state the year is because it is already known by the listener. But just because it's unstated doesn't mean that it isn't critically important.
If you're measuring duration, for example, you will put the largest unit first. The longest serving prime minister of the UK served for 20 years and 315 days. Magellan's expedition around the lasted 2 years, 11 months, and 16 days, if you count from Sanlúcar de Barrameda. The course record for the Iditarod race is 7 days, 14 hours, 8 minutes, and 57 seconds.
And some languages are more irregular than others about numbers. In English, we say "sixteen" where the ones digit is said before the tens digit. French has some base 20 naming conventions that screw up the order, too.
But when we write numbers, we go left to right, largest to smallest. That's why describing time should follow the same convention, and why ISO 8601 exists.
Sure
So you mean that this is the true day krab fries
*shocked pikachu face