Linguistic Usability: Why The American Date Format is Superior

America’s neglect of the imperial system is widely mocked by much of the Western world and for a good reason- it’s batshit illogical. The U.S. is known to disregard worldwide standards in favor of its own quirky and often unintuitive systems of inches, ounces, and gallons. While the majority of the world adheres the popular date format: Day, Month, Year (ex: 4, July, 1776.) The U.S. once again has chosen the unbeaten path by reversing the Day and Month order (ex: July 4th, 1776.) At first glance, this seems like America being America again as this formatting breaks the logical informational hierarchy, but as it turns out it’s actually more usable in the context of everyday communication as it reveals information in a manner that requires less cognitive effort.

In Computer Science, the sequential order in which numerical values are arranged is referred to Endianness.

The Goldilocks Zone

Although the big-endian format for time notation is completely logical, however, logic doesn’t necessarily equate to intuitiveness. Here’s a little thought experiment- your friend invites you on a trip to New York City and you absolutely hate freezing temperatures. I’ll reveal the first part of a date in different formats, you tell me if you’re interested in going on the trip:

A) 2016/**/****
B) 12th/**/****
C) February/**/****
  • “A” is way too broad as the year by itself tells you little information.
  • “B” gives you absolutely no context as the “12th” could belong to any of the 12 months. In both cases, you don’t have enough information to infer anything meaningful until the next piece of information is revealed. Not only does your brain have to do more skipping around in order to get the whole picture, but it has to retain more information before it can make full sense as it waits for the next piece.
  • With the very first piece of info, “C” tells us the part of the year, the season, how far away it is from the present if we have any responsibilities that month, if we’d have enough PTO acquired, etc. Instead of cognitively zooming in, then zooming out, the American standard discloses information progressively in a manner that decreases cognitive load.


Just like dates, time formatting has associated cognitive effort. Different parts of the world use different formats, split mostly between the 24-hour clock or “military time” and the 12-hour clock which appends AM or PM at the end to indicate the time of day.

Here’s a similar thought experiment when it comes to time phrasing:

Imagine your brother calls you from Heathrow airport and asks you if you can pick him up when he lands at 6:30 PM. Just as he tells you the first unit of the time he lands, his phone battery dies. Let’s see what that looks like in the three different time formats:

A) Hey I’ll be landing at 6…*phone disconnects

B) Hey I’ll be landing at half-past…*phone disconnects

C) Hey I’ll be landing at 18…*phone disconnects

  • “A” Even though you didn’t hear the exact time you know it’s at 6. The problem is that you don’t know if it’s 6 in the morning or 6 in the evening. At least you can check all incoming flights for both times.
  • “B” tells you absolutely nothing, as it could be applicable to any one of the 24 hours.
  • “C” on the other hand tells you the exact hour he’ll be landing without further info.

When it comes to communicating time, military time or the 24 hour Clock is superior in succinctness.

Just like any other interface, language has inherent usability which is often overlooked. Good communication can decrease cognitive effort by sparing users from mentally assembling phrases in the right hierarchy and decrease memory retention by sparing them from remembering one chunk as they await the next.