> For the complete documentation index, see [llms.txt](https://docs.wem.io/platform/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.wem.io/platform/wemreference/data-types/date-time.md).

# Date Time

### Description

This is the datatype that stores date and time information. The contents of a date consist of several parts in the following units.

* Year 
* Month 
* Week 
* Day 
* Hour 
* Minute 
* Second 
* Millisecond

 These units can be used in date-time functions in the expression editor.

### Formatting

Formatting of date time values can also be controlled using format strings. Some examples for formatting `'2014-08-21 14:30'` are shown below. 

```
(empty)       /* 21-8-2014 14:30:00 */
MM-dd-yy      /* 08-21-14 */
MMMM d yyyy   /* August 21 2014 */
dddd MMM d    /* Thursday Aug 21 */
d/M/yy HH:mm  /* 21/8/14 14:30 */
hh:mm:ss      /* 02:30:00 */
h:mm tt       /* 2:30 PM */
```

### Unknown

An unknown value can be written as `UnknownDateTime`.

### Examples

```
'2014-08-21'           /* Date without time */
'2014-08-21T14:30:00'  /* Date with time    */
```

### Remarks

The default formatting is determined by the language settings in your [Portal Settings](/platform/wemmodeler/project-settings/portal-settings.md#change-language-settings). 


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