PHP DateTime

Summary: in this tutorial, you’ll learn how to work with the date and time in an object-oriented way.

Introduction to the PHP DateTime class #

PHP provides a set of date and time classes that allow you to work with the date and time in an object-oriented way.

To create a new date and time object, you use the DateTime class. For example:

<?php

$datetime = new DateTime();

var_dump($datetime);Code language: PHP (php)

Output:

object(DateTime)#1 (3) {
    ["date"]=> string(26) "2021-07-15 06:30:40.294788"
    ["timezone_type"]=>  int(3)
    ["timezone"]=>  string(13) "Europe/Berlin"
}Code language: PHP (php)

The DateTime object represents the current date and time in the timezone specified in the PHP configuration file (php.ini)

To set a new timezone, you create a new DateTimeZone object and pass it to the setTimezone() method of the DateTime object:

<?php

$datetime = new DateTime();

$timezone = new DateTimeZone('America/Los_Angeles');
$datetime->setTimezone($timezone);

var_dump($datetime);Code language: PHP (php)

Output:

object(DateTime)#1 (3) {
    ["date"]=> string(26) "2021-07-14 21:33:27.986925"
    ["timezone_type"]=> int(3)
    ["timezone"]=> string(19) "America/Los_Angeles"
}Code language: PHP (php)

In this example, we create a new DateTimeZone object and set it to "America/Los_Angeles". To get valid timezones supported by PHP, check out the timezone list.

To format a DateTime object, you use the format() method. The format string parameters are the same as those you use for the date() function. For example:

<?php

$datetime = new DateTime();
echo $datetime->format('m/d/Y g:i A'); Code language: PHP (php)

Output:

07/15/2021 6:38 AMCode language: PHP (php)

To set a specific date and time, you can pass a date & time string to the DateTime() constructor like this:

<?php

$datetime = new DateTime('12/31/2019 12:00 PM');
echo $datetime->format('m/d/Y g:i A');Code language: PHP (php)

Or you can use the setDate() function to set a date:

<?php

$datetime = new DateTime();
$datetime->setDate(2020, 5, 1);
echo $datetime->format('m/d/Y g:i A');Code language: PHP (php)

Output:

05/01/2020 6:42 AMCode language: PHP (php)

The time is derived from the current time. To set the time, you use the setTime() function:

<?php

$datetime = new DateTime();
$datetime->setDate(2020, 5, 1);
$datetime->setTime(5, 30, 0);

echo $datetime->format('m/d/Y g:i A');Code language: PHP (php)

Output:

05/01/2020 5:30 AMCode language: PHP (php)

Since the setDate(), setTime(), and setTimeZone() method returns the DateTime object, you can chain them like this which is quite convenient.

<?php

$datetime = new DateTime();
echo $datetime->setDate(2020, 5, 1)
    ->setTime(5, 30)
    ->setTimezone(new DateTimeZone('America/New_York'))
    ->format('m/d/Y g:i A');Code language: PHP (php)

Output:

04/30/2020 11:30 PMCode language: PHP (php)

Creating a DateTime object from a string #

When you pass the date string ’06/08/2021′ to the DateTime() constructor or setDate() function, PHP interprets it as m/d/Y. For example:

<?php

$datetime = new DateTime('06/08/2021');
echo $datetime->format('F jS, Y'); Code language: PHP (php)

Output:

June 8th, 2021Code language: PHP (php)

If you want to pass it as August 6th, 2021, you need to use the – or . instead of /. For example:

<?php

$datetime = new DateTime('06-08-2021');
echo $datetime->format('F jS, Y');Code language: PHP (php)

Output:

August 6th, 2021Code language: PHP (php)

However, if you want to parse the date string ’06/08/2021′ as d/m/Y, you need to replace the / with – or . manually:

<?php

$ds = '06/08/2021';
$datetime = new DateTime(str_replace('/', '-', $ds));

echo $datetime->format('F jS, Y');Code language: PHP (php)

Output:

August 6th, 2021Code language: PHP (php)

A better way to do it is to use the createFromFormat() static method of the DateTime object:

<?php

$ds = '06/08/2021';
$datetime = DateTime::createFromFormat('d/m/Y', $ds);

echo $datetime->format('F jS, Y');Code language: PHP (php)

In this example, we pass the date format as the first argument and the date string as the second argument.

Note that when you pass a date string without the time, the DateTime() constructor uses midnight time. However, the createFromFormat() method uses the current time.

Comparing two DateTime objects #

PHP allows you to compare two DateTime objects using the comparison operators including >, >=, <, <=, ==, <=>. For example:

<?php

$datetime1 = new DateTime('01/01/2021 10:00 AM');
$datetime2 = new DateTime('01/01/2021 09:00 AM');

var_dump($datetime1 < $datetime2); // false
var_dump($datetime1 > $datetime2); // true
var_dump($datetime1 == $datetime2); // false
var_dump($datetime1 <=> $datetime2); // 1Code language: PHP (php)

Calculating the differences between two DateTime objects #

The diff() method of the DateTime() object returns the difference between two DateTime() objects as a DateInterval object. For example:

<?php

$dob = new DateTime('01/01/1990');
$to_date = new DateTime('07/15/2021');

$age = $to_date->diff($dob);
var_dump($age);Code language: PHP (php)

Output:

object(DateInterval)#3 (16) {
    ["y"]=>    int(31)
    ["m"]=>    int(6)
    ["d"]=>    int(14)
    ["h"]=>    int(0)
    ["i"]=>    int(0)
    ["s"]=>    int(0)
    ["f"]=>    float(0)
    ["weekday"]=>    int(0)
    ["weekday_behavior"]=>    int(0)
    ["first_last_day_of"]=>    int(0)
    ["invert"]=>    int(1)
    ["days"]=>    int(11518)
    ["special_type"]=>    int(0)
    ["special_amount"]=>    int(0)
    ["have_weekday_relative"]=>    int(0)
    ["have_special_relative"]=>    int(0)
}Code language: PHP (php)

The DateInterval represents the differences between two dates in the year, month, day, hour, etc. To format the difference, you use the DateInterval‘s format. For example:

<?php

$dob = new DateTime('01/01/1990');
$to_date = new DateTime('07/15/2021');

echo $to_date->diff($dob)->format('%Y years, %m months, %d days');Code language: PHP (php)

Output:

31 years, 6 months, 14 daysCode language: PHP (php)

Check out all the DateInterval format parameters.

Adding an interval to a DateTime object #

To add an interval to date, you create a new DateInterval object and pass it to the add() method. The following example adds 1 year 2 months to the date 01/01/2021:

<?php

$datetime = new DateTime('01/01/2021');
$datetime->add(new DateInterval('P1Y2M'));
echo $datetime->format('m/d/Y');Code language: PHP (php)

Output:

03/01/2022Code language: PHP (php)

To format a date interval, you use the date interval format strings.

To subtract an interval from a DateTime object, you create a negative interval and use the add() method.

Summary #

• Use the DateTime class to work with the date and time.
• Use the DateTimeZone class to work with time zones.
• Use the comparison operators to compare two DateTime objects.
• Use the diff() method to calculate the difference between to DateTime objects.
• Use the DateInterval class to represent a date and time interval.
• Use the add() method to add an interval to or subtract an interval from a DateTime object.