Date Formats: Little-Endian, Middle-Endian, Big-Endian

In the Becoming A Proofreader course, we look at how date formats differ between American English and British/Australian English. There are, though, more than three countries in the world, so it’s worth looking at regional date format variations more generally.

Luckily, there are only three basic date format styles you need to know:

• Little-endian (i.e., day-month-year)
• Middle-endian (i.e., month-day-year)
• Big-endian (i.e., year-month-day)

To find out more about regional date formats and proofreading, read on below.

Little-Endian Date Formats

A “little-endian” date format is one that starts with the day (i.e., day-month-year). Authors can write little-endian dates with either numerals or words, although words are more formal:

We held an auction on 15/04/2020 to raise funds for the church.

We held an auction on 15 April 2020 to raise funds for the church.

This is the standard date format in the UK and Australia, as well as in most other countries! It is therefore the correct date format for most English-language writing outside the USA.

Middle-Endian Date Formats

A “middle-endian” date format starts with the month (i.e., month-day-year):

We held an auction on 04/15/2020 to raise funds for the church.

We held an auction on April 15, 2020 to raise funds for the church.

This date format is standard in the USA and some US territories. It’s worth noting, though, that some US-based organizations prefer to use the international date format (more on this below) or a little-endian format (e.g., the US military uses a day-month-year format).

Big-Endian Dates and the International Date Format

A “big-endian” date format starts with the year (i.e., year-month-day). It would be quite rare to see a date written out like this in English, but you may see the numeric version used:

We held an auction on 2020/04/15 to raise funds for the church.

Big-endian date formats are used, for instance, in Asian countries such as China and Japan.

However, this is also the style used by the international date format (ISO 8601). This numeric format provides a standard way of writing dates that works across borders, so it is commonly used by government organizations and global businesses. It always uses the format YYYY-MM-DD, which helps to remove any ambiguity regarding the date denoted:

We received the report on 2020-07-10.

Dates that use this format are sometimes presented as a series of numbers with no dividers:

We received the report on 20200710.

This basic format is fine even if it looks unusual, but consistency and clarity are still important.

Proofreading Regional Date Formats

Ultimately, the date format in a document will usually match the dialect (e.g., little-endian for UK or AUS writers, and middle-endian for US writers). From a proofreading perspective, though, the key things to check in terms of how an author uses date formats are whether:

1. The date format used is suitable for the document’s audience and purpose.
2. Date formats have been used consistently in the document.

If you spot any problems and there is a clear solution (e.g., one date in a document is inconsistent with the others), you can usually correct it directly. Otherwise, simply leave a comment prompting your client to check the date format(s) used in the problem passage.

Becoming A Proofreader

Interested in learning more about proofreading and working as a proofreader? If so, sign up for a free trial of our Becoming A Proofreader course today.

Related posts:

Transatlantic Differences: 3 Tips on UK vs. US Punctuation How to Format Dates in the US, UK and Australia When to Use Italics for Non-English Words When Alright and Anymore Aren’t All Right Any More