Last revised by Daniel J Bell on 10 Sep 2021

Dates may be written in a large number of different ways, which may vary by country, and in some numeric formats may be ambiguous to an international audience. Therefore we insist that all dates are written out in a consistent style, in the format day-month-year, as per the Chicago Manual of Style 1.

Therefore for the first day of the year 2020, we would write:

1 January 2020


  • no ordinal numbers (fancy name given to 1st, 2nd, 3rd, etc...)
  • no commas
  • put the numeric day of the month before the name of the month
  • no abbreviating
    • the name of the month (e.g. Jan for January)
    • the year (e.g. '20 for 2020)
  • no Roman numerals

There are many alternatives listed below which we would prefer not to be used:

  • 1 January, 2020
  • 1st January 2020
  • 1st January, 2020
  • 1st January, 2020
  • January 1 2020
  • January 1, 2020
  • January 1st 2020
  • January 1st, 2020
  • January 1st 2020
  • January 1st, 2020

The abbreviation CE (Common Era) is not required, unless for the very rare instances in which the dates of birth and death straddle the years 1 BCE (Before CE) to CE. Remember there is no year 0, therefore the calendar passes from 1 BCE to 1 CE. 

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