Metadata Input Guidelines: Date

Element Name



Dates associated with events in the life cycle of the resource.

Where Can the Date Information be Found?

Item Type Information Sources Creation date for this kind of item is the date or range of dates when:
For text
  • title page
  • copyright page
  • cover or inside cover page
the text was published, printed, or revised
For images
  • bottom or back of a photograph
  • a time-stamp
  • envelope, slip cover, or case

a photograph or slide was taken
For maps
  • title in a caption or legend
  • notes around the outside of the map
the map was printed
For music scores
  • top of page
  • title page
  • table of contents
the music was finished (handwritten) or printed
For videos
  • title or credit screen(s)
  • label on disc
  • container cover
the video was released
For sound files
  • information on disc/cassette
  • container information
the disc/tape was issued
For computer files
  • title page/screen
  • statement in a header/footer
the content was finished

In some cases the date may come from accompanying or supplementary information.

How Date Works in the Metadata Form

1. Date qualifier – drop-down menu
2. Date – text field
Yes - to include different kinds of date information, click ‘Add’ to repeat all field parts; each individual date type (creation, submission, harvested, etc.) should not be repeated
No - also see more information about required fields

How Should the Date be Filled in?

General Date Rules

  • If no date can be found, leave the field blank
  • For each date, be sure to choose the appropriate date type from the controlled vocabulary
  • Always format dates appropriately:
Guideline Form(s) Examples
Basic Format
  • Write dates Year-Month-Day, separating the sections with a single hyphen
YYYY-MM-DD 1985-03-27
  • Include partial dates only if the year or only the month and year are known

Date Ranges
  • Date ranges are inclusive (e.g., a scrapbook or collection of items compiled over a period of time)
  • Follow the same basic format but separate the dates with a slash mark
YYYY-MM-DD/ YYYY-MM-DD 1941-12/1945-08
  • If part of the date range is unknown, one date can be replaced by a double-dot to designate an "open" range


General Ranges/Time Periods
  • "One of a Set" dates represent a specific unknown date during a known time period (e.g., a photograph taken on a specific day sometime between 1897 and 1901)
  • Dates are enclosed in [square brackets] and separated by commas
  • Dates can be at any level of specificity: year, year and month, or year, month, and day


  • Two periods can be used to represent a specific point within all of the years before/after two dates, such as:
    • Between 1897 and 1901
    • Before or during 1897
    • During or after 1901




  • Please note: Due to this functionality, [square brackets] can no longer be used to represent dates added by a metadata creator*
Uncertain dates
  • If a date is uncertain, a question mark can be used at the end of the date
YYYY-MM-DD? 1958-09-16?
  • If a date is approximate (e.g., "circa" dates), a tilde can be used at the end of the date
YYYY-MM-DD~ 1879-03-29~
  • Unknown digits
    • Any unknown digit can be replaced with a "X"
    • If only a decade is known, the last digit of the year can be replaced with a "X" (YYYX)*
    • Dates with unknown digits cannot also be approximate

  • For seasonal dates (rather than months), use the following codes:
    • 21 -- Spring
    • 22 -- Summer
    • 23 -- Autumn
    • 24 -- Winter
YYYY-SS 1991-23

Dates with timestamps
  • If the item has an exact time associated with it, use 'T' to separate the date and time
  • This must be exact
YYYY-MM-DDThh:mm:ss 2008-05-02T15:07:51
B. C. Dates
  • Include a hyphen at the front of the date
  • Years must have at least four digits
-YYYY-MM-DD -0601

*For more information about implementation of the date standard, see the Comments below.

Complex Dates

If you have dates that are approximate, uncertain, or complicated in other ways, it can be difficult to choose the most appropriate formatting. This chart is framed for “creation” dates, but applies to any kind of date, to help explain which format is best to express a date.

If the item was created: Such as: Use: Example: This means:
During a known time of year A serial issue from fall 2004 (no listed publication month) Seasonal date 2004-23 Autumn 2004
During a known decade A hat from the 1920s Unknown digit 192X 1920s
At an approximate date A manuscript written circa 1846 Approximate date 1846~ Approximately 1846
At a known but uncertain date A photograph believed to have been taken in 1963 based on context Uncertain date 1963? 1963?
During an approximate uncertain date A map believed to have been drawn circa 1910 Uncertain/approximate date 1910% Approximately 1910?
Over a period of time A scrapbook compiled 1980-1985 Date range (interval) 1980/1985 1980 to 1985
During an approximate decade A photograph taken circa 1940s Date range (interval) 1940~/1949~ Approximately 1940 to approximately 1949
During any approximate date range A letter written circa 1887-1890 Date range (interval) 1887~/1889~ Approximately 1887 to approximately 1889
At a specific time within a known range A map drawn between 1900 and 1920 One of a set [1900..1920] Between 1900 and 1920
A photograph taken at an event held September 12-15, 1974 [1974-09-12..1974-09-15] Between September 12, 1974 and September 15, 1974
At a specific time during a number of dates A photograph taken in December, either 1954 or 1958 One of a set [1954-12,1958-12] December 1954 or December 1958
At multiple known dates or range(s) A page with two newspaper clippings from 1902 and November 12, 1920 Multiple dates {1902,1920-11-12} 1902 and November 12, 1920
A scrapbook compiled during a student's senior year 1927-1928 with notes from the start of the next fall {1927-08..1928-05,1928-09} August 1927 to May 1928 and September 1928

Determining Creation Dates

  • Whenever possible, enter an original resource creation date
  • Be sure to select “Creation” as the date type from the drop-down menu
  • If the creation date is unknown, leave the field blank
  • When the resource being described is a collection, a date range can be used to describe the creation date range of all the resources

  • Creation date refers to the date of the exact item described in the record, even if it is a derivation:
    • If the item is a reprint or revision of an original text:
      • Use the date of the reprint/revisions
      • Include a note about the original text and printing date
    • If the item is a copy negative:
      • Use the date that the copy negative was created
      • The date of the original photographs may be used in coverage
  • A note about postcards and greeting cards:
    • If there is no letter or message written on the card:
      • The item is treated as a photograph or piece of artwork
      • Use the date that the photograph was taken or the drawing was done
    • If the card has a letter or message written on/in it:
      • The item is treated as a piece of correspondence
      • Use the date that the letter was written or that the card was postmarked
      • If it is important, the date of the picture can be included as part of the coverage

Non-Creation Dates

  • Use other types of dates only when they are relevant:
    • Date Harvested - Date that a web-resource was captured for archival purposes
    • Submission Date - Date that the item was submitted for approval by an organization, institution, or agency
    • Acceptance Date - Date that the item was approved by an organization, institution, or agency
  • Submission and acceptance dates are primarily used for patents, but may be used for other items when appropriate
    • For patents, the acceptance/approval date and creation date are the same. This may not be true for all items.
  • In certain cases, items cannot be made publicly available due to publisher requirements, privacy issues, or other strictures. The Embargo Until Date represents the first date that an item will become accessible to the public or a pre-specified user group. See also Rights Access

Other Examples

[Letter from Zavala to Santa Anna, March 7, 1829]
Original Resource Creation Date: 1829-03-07
Painting: A Scene from “The Beggar’s Opera”
Original Resource Creation Date: [1728..1729]
Digital photograph: [Bull riding at the Cowtown Coliseum]
Original Resource Creation Date: 2003-12-27T09:16:40
Court case: Documents pertaining to B. C. Wallace as the receiver of the estate and guardian of Campbell minors, cause no. 532, 1896-1904
Original Resource Creation Date: 1896-11-13/1904-12-08
Farmer’s bulletin: Diseases of sheep and goats.
Original Resource Creation Date: 1943-09
University catalog: Catalog of Hardin-Simmons University, 1989-1990 Undergraduate Bulletin
Original Resource Creation Date: 1989
Photograph: Crazy Theatre With Car
Original Resource Creation Date: 1914~
Postcard: [Hamilton Hotel, Laredo, Texas]
Original Resource Creation Date: 1910-01-23
Archived website: U.S.-Canada Power System Outage Task Force
Original Resource Creation Date: 2004
Date Harvested: 2009-07-01
Patent: Improvement in Medical Compounds or Bitters for Treating Chills and Fever.
Original Resource Creation Date: 1873-05-20
Submission Date: 1873-04-05
Acceptance Date: 1873-05-20


  • To express the time period(s), date, or date range associated with the intellectual content of the resource, use the Coverage element.
    • For example, a book published in 1976 that is about Texas history from first statehood to 1964 would have an original resource creation date of 1976, but a coverage date range of 1846 - 1964.
  • Recommended best practice for encoding the date value is defined in the ISO-approved extension, available at from the Library of Congress: Extended Date/Time Format (EDTF)
    • As of November 2020, the UNTL edit system validates against the approved standard rather than the draft specifications
    • Currently all levels (0 through 2) are supported by UNT Libraries metadata guidelines
      • As of April 2013, the use of [brackets] to represent dates from a source other than the item is no longer permitted in order to support Level 2 functionality
      • This notation has been common practice in traditional library cataloging (using AACR2)
      • To document the fact that a creation/publication date has been added by a metadata creator, a Display Note can be added with text such as “Publication date is not printed on the {item type}.”
    • Local standards for uncertain dates differ slightly from level-1 EDTF extensions:
      • It is valid for the two right-most digits to be “unknown” (e.g., YYXX) however, it is preferred that the date represent at least a decade-level date in order to be helpful for users.
      • This rule also applies to month and day, but it is preferred to revert to the known date level with the assumption that additional granularity/specificity is unknown, e.g.:
        • Represent a year with an unknown month (YYYY-XX) as a year only: YYYY
        • Represent a year and month with an unknown day (YYYY-MM-XX) as a year and month only: YYYY-MM
      • Additionally, the extension allows for ranges to be “unknown” by leaving one side of the range blank vs. “open” using a “..” in place of one date. Generally, local standards prefer the “open” option to denote an explicit choice vs. accidental “/” punctuation.


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