Dates may be formatted differently depending on where they are used. In all cases, years should be expressed with 4 digits unless part of a proper title. For more guidance 

Formatting for Narrative Fields

Dates in narrative text (i.e., notes) follow a month, day, then year format. When citing year ranges, do not use dashes and include all digits. Examples follow:

• October 12 (not October 12th)
• October 12, 1952  (when used in narrative the year should be followed by a comma)
• September 1990 (no comma)
• 1980s (no apostrophe)
• 1872 to 1888 (not 1872 to 88)
• from 1940 to 1960
• between 1980 and 1990
• The 21st century; 21st-century technology

Formatting for Collection Level Description and Component Lists

Normalized Dates

In normalized fields, all dates should be entered in the ISO 8601 Standard, as follows:

• general-to-specific approach — the year first, followed by month, then day
• each element is separated by a hyphen ("-")
• Numbers less than 10 are preceded by a leading zero
• YYYY or YYYY-MM  or YYYY-MM-DD 

Date Expressions

If date is approximate, includes months and days, and/or includes significant gaps in date ranges a date expression should also be entered. Dates are still formatted as year - month  - day, however the month should be written out. Do not repeat years or months in expressions of date ranges. Semesters may also be referenced in the date expression.

• 2014 July 12-14
• 2007 August 12 - October 31
• 2009 April 5 - 2010 May 1
• 2016 September
• 2015 Fall

Note any significant gaps in date ranges. Separate single dates or ranges with a comma.

• 1903, 1950-1955
• 1965, 2009

For approximate dates, add qualifiers.

• circa 1952-1978
• circa 1975 August
• 1892 or 1893
• before 1920
• after 1920
• 1980s

If a date is not able to be determined, use "undated."

Using the Date Module

Add new date to a collection, series, file, or item by clicking the “Add Date” button.

Field	About
Label	Label is set to "Creation" by default. The label specifies the type of date being entered (e.g., date published). Choose as appropriate.
Date Expression	Expression is an open text field to enter a natural language expression of the date. It is used when date is unable to be determined, approximate, includes significant gaps in date ranges, and/or includes months.
Type	Choose the type of date to be entered: Option When Used Bulk Dates Rarely used at file level. Date range is applicable to the majority of materials in the description level, excluding any outliers on either end. Inclusive Dates Date range is applicable to all materials in the unit being described, including outliers on either end. Single Use if there is only one date for all materials in the unit described.
Begin	Normalized date field. Numerical value of earliest (or only) creation date in the accession in ISO 8601 Standard Formatting: YYYY, YYYY-MM, or YYYY-MM-DD. 2018-01-01 (in expression field: 2018 January 1) 1975-05 1998
End	Normalized date field. Numerical value of last creation date (if applicable) in the accession in ISO 8601 Standard Formatting: YYYY, YYYY-MM, or YYYY-MM-DD.
Certainty	Choose "Approximate" if the dates are estimated or uncertain for any reason.