The default representation of dates is a compact string such as 20211002153802059. The associated template is [UTC]YYYY0MM0DD0hh0mm0ss0XXX. For example, the created and modified fields are stored like this.

The display format for this string can be controlled with a template. For example, transcluding the modified field automatically applies a template to display the date as Sat Oct 02 2021 17:40:50 GMT+0200 (Central European Summer Time). A few widgets and filter operators allow you to manually specify a template, for example the ViewWidget:

<$view field=modified format=date template="DDth mmm YYYY 0hh:0mm:0ss" />

The date string is processed with the following substitutions:

Note that other text is passed through unchanged, allowing commas, colons or other separators to be used.

The {era:BCE||CE} notation can specify different strings for years that are negative, zero or positive. For example {era:BC|Z|AD} would display BC for negative years, AD for positive years, and Z for year zero.

Examples

Using TIMESTAMP to calculate time difference

You can calculate the difference between two dates by doing the following:

1. Convert both dates to timestamps
2. Subtract the later date from the earlier one – if you don't know which one is earlier use the abs operator to get an absolute value after subtraction
3. Divide the resulting number by the number of milliseconds in your chosen interval

Here is an example of calculating the number of days that passed between creation and last modification of current tiddler:

• Convert the created and modified fields to timestamps
• Divide their difference by 86400000 which is the number of milliseconds in a day
  • 1000 milliseconds per second × 60 seconds per minute × 60 minutes per hour × 24 hours per day = 86,400,000 milliseconds per day

<$let
	timestamp-modified={{{ [{!!modified}format:date[TIMESTAMP]] }}}
	timestamp-created={{{ [{!!created}format:date[TIMESTAMP]] }}}
	difference-days={{{ [<timestamp-modified>subtract<timestamp-created>divide[86400000]floor[]] }}}>

* ''Modified date:'' <$text text={{{ [{!!modified}format:date[YYYY-0MM-0DD]] }}}/>
* ''Created date:'' <$text text={{{ [{!!created}format:date[YYYY-0MM-0DD]] }}}/>
* ''Difference in days:'' <<difference-days>> days
</$let>