Supported Date Formats

Preceden supports a wide variety of date and time formats.

Quick Tips for Formatting Dates & Time

Here are a few quick notes on the date/time formats we support:

  • Where months are spelled out upper or lower case and abbreviations are supported.
  • Commas, either in dates, or used to delineate large years, are optional.
  • Years can be shortened to two digits, but note: 29 to 99 will be interpreted as 1900s, 00 to 28 as 2000s.
  • For the years 1 - 99 AD, you need to include the AD after the year (to tell it apart from the shortened modern years).
  • Spaces before BC/AD/etc., are optional as are those before AM and PM.
  • Preceden supports dates ranging from 240,000 BC to 240,000 AD.
  • When you specify an end date for an event, Preceden assumes you want the event to include that end date (learn more).

Date Formats

  • 2022
  • May 2022
  • 5/2022
  • May 8, 2022
  • May 8th, 2022
  • 5-8-2022
  • 2022-05-08
  • 05.08.2022
  • 5/8/2022 - Note that this is MM/DD/YYYY which we use in the US; if your country uses DD/MM/YYYY you may want to use the next format
  • 8 May 2022 - You can use this format if your country uses a DD/MM/YYYY format.
  • 8th of May 2022
  • 8 de Mayo 2022
  • 8 de Mayo de 2022
  • 60,000 BC - We support BC, BCE, BP, FVT, AD, CE, AC, DC, EVT; periods and spaces between the letters are optional.
  • If you set the start date to Today it will start at the beginning of the current UTC date. If you set an end date to Today, it will end at the end of that day.
  • If you set the start date or end date to Now it will reflect current date and time (compare that to Today, which only reflects the current date). 
  • You can also enter the start and end date in the start date field separated by a hyphen and Preceden will automatically split them into the start and end date: 2018 - 2022.
  • Additionally, you can enter a start date such as 1940s and it will automatically be split into 1940 to 1949 when the event is created.
We also support a variety of month names in other languages. If yours is not currently supported, please drop us a note and we'd be happy to add support for your language.

Time Formats

When the date is specified, you can also include a time:
  • May 8, 2022 1pm (pm and PM both work)
  • May 8, 2022 1:23pm
  • May 8, 2022 1:23:05pm
  • May 8, 2022 13:23:05 (when no AM or PM is specified, it's assumed to be 24 hour time)


For event end dates, Preceden also supports durations which are automatically added to the event's start date. Here are a few examples:

  • 2 seconds
  • 8 minutes
  • 5 hours
  • 3 days
  • 7 weeks
  • 9 months
  • 1 year
  • 2 years 8 months 1 day 5 minutes
  • 10 weekdays - to have Preceden not count weekends when determining the end date

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