DateTime
DateTime::__construct
DateTime
PHP Manual

# DateTime::add

# date_add

(PHP 5 >= 5.3.0, PHP 7)

DateTime::add -- date_add — Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object

### Description

Object oriented style

public DateTime DateTime::add ( DateInterval `$interval` )

Procedural style

DateTime date_add ( DateTime `$object` , DateInterval `$interval` )

Adds the specified DateInterval object to the specified DateTime object.

### Parameters

`object`

  Procedural style only: A DateTime object returned by date_create(). The function modifies this object.

`interval`

  A DateInterval object

### Return Values

Returns the DateTime object for method chaining or `FALSE` on failure.

### Examples

Example #1 DateTime::add() example

Object oriented style

`<?php
$date = new DateTime('2000-01-01');
$date->add(new DateInterval('P10D'));
echo $date->format('Y-m-d') . "\n";
?>`

Procedural style

`<?php
$date = date_create('2000-01-01');
date_add($date, date_interval_create_from_date_string('10 days'));
echo date_format($date, 'Y-m-d');
?>`

The above examples will output:

    2000-01-11

Example #2 Further DateTime::add() examples

`<?php
$date = new DateTime('2000-01-01');
$date->add(new DateInterval('PT10H30S'));
echo $date->format('Y-m-d H:i:s') . "\n";
$date = new DateTime('2000-01-01');
$date->add(new DateInterval('P7Y5M4DT4H3M2S'));
echo $date->format('Y-m-d H:i:s') . "\n";
?>`

The above example will output:

    2000-01-01 10:00:30
    2007-06-05 04:03:02

Example #3 Beware when adding months

`<?php
$date = new DateTime('2000-12-31');
$interval = new DateInterval('P1M');
$date->add($interval);
echo $date->format('Y-m-d') . "\n";
$date->add($interval);
echo $date->format('Y-m-d') . "\n";
?>`

The above example will output:

    2001-01-31
    2001-03-03

### Notes

DateTime::modify() is an alternative when using PHP 5.2.

### See Also

- DateTime::sub() - Subtracts an amount of days, months, years, hours, minutes and seconds from a DateTime object
- DateTime::diff() - Returns the difference between two DateTime objects
- DateTime::modify() - Alters the timestamp

DateTime
DateTime::__construct
DateTime
PHP Manual