# Date Operators

Date operators allow you to handle information concerning time. You can use them to set or calculate a moment in time, determine the number of days in between two dates or format how a date should be displayed.

### ISO8601 Format

ISO8601 is the international standard format for date or a date and time ([wikipedia](https://en.wikipedia.org/wiki/ISO_8601)). The values are ordered from the largest unit of time to the smallest: year, month, day, hour, minute and second. 

#### Date

A date is given as `YYYY-MM-DD`, for example `2016-02-29` (the founding date of Atfinity AG). 

#### Time and Date

If you need a date with a time, the format would be `YYYY-MM-DDThh-mm-ss`, so a date and a time separated by a `T`. For example`1999-06-25T09:52:08`.

#### Using ISO8601

If dates are given to Atfinity as text, they always need to be in ISO8601 format. If a function in Atfinity returns a date, it will always be in ISO8601 format. If you want to return anything from Atfinity in a different format you can use [FORMAT\_DATE](https://docs.atfinity.io/rule-language/operators/date-operators/format_date) to format the output to your liking.