How to Convert a Date to Timestamp in PHP

Use the strtotime() Function

You can use the PHP strtotime() function to convert any textual datetime into Unix timestamp.

The following example demonstrates how this function actually works:

<?php
$date1 = "2019-05-16";
$timestamp1 = strtotime($date1);
echo $timestamp1; // Outputs: 1557964800
$date2 = "16-05-2019";
$timestamp2 = strtotime($date2);
echo $timestamp2; // Outputs: 1557964800
$date3 = "16 May 2019";
$timestamp3 = strtotime($date3);
echo $timestamp3; // Outputs: 1557964800
?>