PHP strtotime() Function – Converting Text to Timestamp [With Examples]

The PHP strtotime() function takes a string containing text and converts it to a Unix Timestamp. Find out how to use this function in this guide.

A Unix timestamp is a number representing the number of seconds since 00:00:00 UTC on 1 January 1970. From it, you can build more complex Date/Time objects which can readily provide Dates/Minutes/Hours/Seconds or other information about the supplied time.

strtotime Syntax

strtotime ($datetime , $baseTimestamp)

Note that:

• $datetime is your supplied text string (possibly) containing a date
  • strtotime() supports the English language only
  • See here for a comprehensive list of compatible formats
  • ..or see below for some real-world examples
• $baseTimestamp is the Unix timestamp used as a base which relative dates are calculated from
  • It is optional
• strtotime() will return a Unix timestamp (a number) if it succeeds in parsing your input or FALSE if it fails
  • No timezone information is included in the returned Date object
  • You should add some by converting the timestamp into a DateTime object and adding the timezone data as applicable
• Any date or time supplied to strtotime() is assumed to be in the system default timezone as configured in PHP

strtotime Examples

Here’s a few examples of using strtotime():

echo strtotime("now"); # Outputs the current Unix timestamp

echo strtotime("23 December 2007"); # Unix timestamp for a given date

Relative Times

You can also get the time for a date relative to the current:

echo strtotime("+1 day"); # Outputs the Unix timestamp for todays date, plus a day
echo strtotime("+1 week 3 days 2 hours 1 seconds"); # Multiple units can be supplied
echo strtotime("next Tuesday"); # Textual descriptors are supported - see the comprehensive list above for which words will work
echo strtotime("last Wednesday");

Converting to a Date object with Timezone Info

$date = new DateTime(); # Create a new DateTime object - it will default to the current time
$date->setTimestamp(strtotime("next Tuesday")); # Set the time via strtotime
$date->setTimezone(new DateTimeZone('Australia/Sydney')); # Add timezone information
print_r($date); # $date is a DateTime object, not a string, so it can't just be echo'd - print_r prints the object properties recursively

Conclusion

Converting text representations of times to something a computer can run calculations on is a common task. It’s used when reading and calculating dates from a database or file and is often used for checking a user’s age from their birthday or checking whether a database record falls into a specific date range.

For more examples, check out the official PHP strtotime() documentation at:

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

…and be sure to check out our other PHP articles!