The American Date Format

The American date format is a mystery. Why is it written in such an format? There must be some reason behind it. We didn’t start writing dates month first just because some millennials at an over-valued startup decided it was cool. It’s been around a long time. The date at the top of the Declaration of Independence was written as July 4, 1776.

What is today’s date? Depending on who you ask, and where they live in the world, they will write it differently. You don’t need to live in the US to know that, both people and organizations, format their dates differently in the US than the rest of the world. In the US, today’s date, December 11th – 12/11/2016 – is written month first, then the date, then the year. How does the rest of the world format their dates? In a word? logically. Some countries put the year first, then the month, then the day. Others start with the date, then the month, then then the year. In Latin America, today’s date would be written as 11/12/2016. In Asian countries where the year-month-day format is preferred, today’s date is 2016/12/11. So why does the U.S. start with the month? I’ve been thinking about that.

When you think about time in a short scale – on a daily basis — the day-month-year format makes the most sense. You might be planning something 2 days or a week from now. That first number in the date makes it easy to calculate. The difference between 4/12/2016 and 11/12/2016 is 7 days.  While the units of time increase, their usefulness decreases. You’ll rarely need to think about the year if you spend most of your time thinking about difference between days or weeks.

When you take a long view of time, the year-month-day format is the most logical choice. It allows you to compare dates easily over time. Computers sort dates in this format naturally — which provides a great value for reports and filenames. As more and more data comes online, this year-month-date format becomes increasingly important. So much so it’s used by standards bodies like ISO and W3C. They use it in data formats for consistency in exchanging data. The year-month-date format is the best format to use for historical and archival purposes.

The U.S. date format of month-day-year is most effective you when you constrain your events to a particular 12-month period. Today is December 11. If you’re planning something for April 7, you know that April is 4 months away.  You don’t care so much, at the moment, that your event is on the 7th. As you get closer you to April 7, the day of the month becomes more important. In this context, the year is the least important part of the date — therefore it gets moved to the end of the date format. When you go beyond a particular 12-month period, then the year becomes useful. You still need to know which year an event occurred.

There you have it. Those are some thoughts on the American date format. Hopefully, that helps it seem a little more logical.