PHP date() Function

What is PHP date() Function?

If you want to format a specific time to a human readable format, use PHP date() function. Example, 5 January 2024, 12/27/2023, 7:!5 am etc. The function actually takes a timestamp and converts it to your desirable date and time format. Now, you may ask what the timestamp is.

Timestamp: Timestamp of a specific time is the number of second from 1^st January 1970 00:00:00 Greenwich Mean Time (GMT) to that specific time. 1^st January 1970 00:00:00 Greenwich Mean Time (GMT) is known as Unix Epoch.

So, from a timestamp (which is just a number of some seconds) we human can’t read a date. We need to convert this seconds to a date and time format. And PHP date() function helps us to accomplish this.

Syntax:

date(format, timestamp)

Parameters:

format (required): This is a string. It is the format how you want the date to be displayed.

The PHP date() function uses some English alphabet letters to construct different parts of a date and time. When using in the “format” parameter, they carry special meaning. Check the “Formatting letters / Characters” table below for the full character list with their meaning and examples. Check example 1 to see the formatting characters in action.

timestamp (optional): This is an integer which is an UNIX timestamp. It could indicate any time in the past or in the future. Check example 2. By default, the function uses local time as timestamp. That means, if you don’t mention this parameter, the function uses the local time as the. You can get the current local timestamp from time() function. timestamp Check example 3.

Table: Formatting Letters / Characters

Return Values:

The formatted date of the timestamp –

• specified in the second parameter, or
• of the local time if the second parameter is not specified.

Examples:

Example 1:

<?php
echo date("m-j-Y g:i:s a");
echo "<br />";
echo date("d F Y g:i A");
echo "<br />";
echo date("dS F Y");
echo "<br />";
echo "We're in the week: " . date("W");
echo "<br />";
echo date("Y-m-d");
echo "<br />";
?>

Output:

12-28-2023 8:07:51 am
28 December 2023 8:07 AM
28th December 2023
We’re in the week: 52
2023-12-28

Example 2:

<?php
echo date("m/j/Y g:i:s a", 1703728397);
?>

Output:

12/28/2023 7:53:17 am

Explanation:

The date and time is retrieved from the timestamp provided in the second parameter.

Exercise 3:

<?php
echo date("\D\a\\t\\e: m-d-Y, \T\i\m\\e: g:i:s a");
?>

Output:

Date: 12-28-2023, Time: 8:07:51 am

Explanation:

Characters inside the date() function are escaped with the \ character so that they don’t conflict with the regular formatting characters.

Exercise 4:

<?php
date_default_timezone_set('UTC');
echo date("m-j-Y g:i:s a");
?>

Output:

12-28-2023 2:31:57 am

Explanation:

After setting the timezone as UTC, the date() function in the next line displaying the date and time is showing according to the UTC time zone.

Practical Usages of date() Function:

We use date and time everywhere.  Few real life examples are-

• To display postdate or update date of an article.
• To create a date and time before adding a new entry in the database table.
• To control different functionalities of an event like displaying the discount code in the black Friday only etc.

Notes on date() Function:

• You can’t specify time zone using date() function. For this, use PHP DateTime class.
• By default, date() function uses server’s local time zone. If you want to work on a different time zone, use date_default_timezone_set() function to set another time zone.
• The timestamp parameter is useful for finding specific point of time in the past or in the future. Check example
• Other than the above formatting characters, following characters are also used between the characters above to add extra formatting to make it more readable. Check any example.
• As part of the date, you can use letters inside date() function. But, to differ these characters from the formatting characters, you’ll escape it by adding a backslashes(\) in front of each character. Check example 3.
• If your server is in different timezone than yours, you’ll get a different time. To get the current time, set your PHP script for your desire timezone with the date_default_timezone_set() function. After this, you’ll get date and time according to this timezone. Check example 4.

PHP Version Support:

PHP 4, PHP 5, PHP 7, PHP 8

Summary: PHP date() Function

The date() function may be the most commonly used built-in PHP date and time function. This function is an indispensable part of each PHP script that deals with date and time. The date() function helps you to construct a date according to your requirements.

Reference:

https://www.php.net/manual/en/function.date.php

https://www.php.net/manual/en/datetime.format.php