There’s not much information on this topic, but I've done a lot of research and can now say with confidence that I have the answer:
Although the best date format depends on context. The least confusing, easiest to read format is Thursday, 1 January 1970.The day of the week in full, followed by day of the month in plain numbers, the full name of the month, and then the year in full.
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Keep reading if you want to know why this format is the best.
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the best date formatThursday, 1 January 1970
the best time and date format00:00:00 — Thursday, January 1st 1970
Note — While writing this I discovered that google gives you the same format if you google "what date is it?" Which I've taken as a good sign.
It's the most readable, easily scannable, and least confusing to the most amount of people. But it doesn’t look particularly cool, new, or surprising. So why is it the best?
For an answer to that, we first have to dive into the strange world of endianness.
Generally speaking, dates and times are shown with the smallest unit on the left, and largest unit on the right. This is the little endian format.
Seconds, Minutes, Hours, Days, Months, Years
Most digital clocks have it the other way round. The largest unit on the left and the smallest units on the right. This is called big endian.
Years, Months, Days, Hours, Minutes, Seconds
The word endianness is borrowed from the novel Gulliver's Travels. In which a civil war breaks out among the Lilliputians over which end to crack open a boiled egg 🥚 the little end or the big end.
The two sides of the war are known as little-endians and big-endians.
Obviously, this is satire. There is no right end. But I think we can all agree that you must never crack a boiled egg open from the middle. Right? RIGHT?
For some strange reason that no one can fathom, everywhere on Earth uses either little endian or big endian to format the date, except for the USA.
The US formats dates using the paradoxically named middle endian format.
Seconds, Minutes, Hours, Months, Days, Years
It is hard to find an explanation for this absurdity. Imagine, if all US clocks showed the time like this:
It would be infuriating.
Unfortunately, because of the conflict of endianness, writing the date as numerals only causes international confusion.
table of confusion
…there could be something to that.
It appears that the document asserting United States' independence from the British uses the middle endian format.
Looks pretty good written out like that—and it's practically impossible to misinterpret the date.
This is because writing the name of the month in full, distinguishes it from the day and the year. We've just stumbled upon our first clue to finding the best format, but we're not there yet.
The day and the year are just a stray comma away from being confused, especially if your date is before the year 32AD. Things get worse if you add the day of the week.
Not quite good enough date format
Thursday, January 1, 1970
Another lesson we can learn from historical US legal documents is: Don't use commas when they're not needed.
Just look at the The Twenty Sixth Amendment of the US constitution:
“The right of citizens of the United States, who are 18 years of age or older, to vote, shall not be denied or abridged by the United States or any state on account of age.”
Taken literally, it means anyone in the world over the age of 18 is a US citizen. I wouldn't bet on that argument working at border control.
One way of removing that second comma, is to use an ordinal indicator, which is the fancy name for the st, nd and rd bits of 1st, 2nd and 3rd.
Slightly better date format
Thursday, January 1st 1970
That is slightly better. But we've got to fix that offensive middle-endianness.
Even better date format
Thursday, 1st January 1970
Great. We're so close now. Just one more step to the perfect format.
Without contrast between written elements, reading becomes hard. Over the centuries, since the advent of the written word, we’ve developed lots of ways of creating contrast.
First we used size to differentiate the most important elements, like headings.
Then came punctuation and spaces, to seperate paragraphs and words.
Then lowercase and UPPERCASE, small caps, boldface, italics, and underlining.*
*Underlining is bad, see underline generator.
To illustrate how important these are to creating scannable text, see how hard it was to read the paper in ancient Rome:
You can’t use most of these methods of creating contrast when formatting the date. It would look jarring, and probably isn’t an option.
Instead, you can use juxtaposed numerals and letters to create contrast—abc 123. All we need to do to achieve this is remove the ordinal indicator.
I like ordinal indicators. They look stylish and using them makes me feel important. But this isn't a quest for the classiest date format. So here we are:
The Best Date Format
Thursday, 1 January 1970
Psst—the comma is optional.
If you need to use another language, the same format works just fine.
Le meilleur format de date
jeudi, 1 janvier 1970