> ## Documentation Index
> Fetch the complete documentation index at: https://www.integrate.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# ETL: DateAddDays

> Use the DateAddDays expression function in Integrate.io ETL to add or subtract days from a date or timestamp value within your pipeline transformations.

## Description

Returns a datetime value that is the result of adding a specified number of days to a datetime expression.

## Syntax

`DateAddDays(datetime_expression, days)`

## Arguments

*datetime\_expression* - string expression in ISO 8601 format.

*days* - integer expression representing the number of days to add. Use a negative value to subtract days.

## Examples

`DateAddDays('2009-01-07T01:07:01.000Z', 10)` returns '2009-01-17T01:07:01.000Z'

`DateAddDays('2009-01-07T01:07:01.000Z', -5)` returns '2009-01-02T01:07:01.000Z'

## Notes

datetime\_expression must be in ISO 8601 date time format, otherwise the job will fail. See [Using ISO 8601 date/time functions](/etl/using-iso-8601-string-functions/).

## Return value datatype

String (ISO 8601 format)

## Impact of null value

If any (or all) inputs are null, returns null.