Looping through dates in PHP.

This is a tutorial on how to loop / iterate through a period of dates in PHP. In this guide, we will loop through all of the dates that fall between our specified start date and end date.

Take a look at the PHP code snippet above:

<?php

//The date that you want to start at.
$start = '2010-01-01';

//The date that you want to stop at.
$end = '2015-12-31';

//We set our counter to the start date.
$currentDate = strtotime($start);

//While the current timestamp is smaller or equal to
//the timestamp of the end date.
while($currentDate <= strtotime($end)){
    
    //Format the timestamp and print it out
    //for illustrative purposes.
    $formatted = date("d-M-Y", $currentDate);
    echo $formatted, '<br>';
    
    //Add one day onto the timestamp / counter.
    $currentDate = strtotime("+1 day", $currentDate);
}

Explanation:

1. We specified the date that we want to start at. In this case, it is 2010-01-01.
2. We specified the end date. i.e. The date that we want our loop to stop at. You could set this to today’s date by using date(“Y-m-d”);
3. Our $currentDate variable contains the UNIX timestamp of the date that we are currently looking at. This variable will obviously change as we iterate through our dates.
4. The logic behind our while loop is pretty simple. We basically tell it not to stop until the timestamp is equal to the timestamp of our end date. If our $currentDate variable contains a timestamp that is greater than the timestamp of our end date, the loop will stop. Remember: A Unix timestamp will increase as time goes on, simply because it contains the number of seconds that have passed since the 1st of January 1970. i.e. Yesterday’s timestamp will be a smaller number than today’s timestamp.
5. We print out a formatted version of the timestamp for example purposes. This is where you would carry out the logic of your application.
6. We set the timestamp of our $currentDate variable to the next day.