WeberTrivia.com -> PHP Manual -> Parse about any English textual datetime description into a Unix timestamp

Description

int strtotime ( string $time [, int $now ] )

The function expects to be given a string containing an English date format and will try to parse that format into a Unix timestamp (the number of seconds since January 1 1970 00:00:00 UTC), relative to the timestamp given in now, or the current time if now is not supplied.

This function will use the TZ environment variable (if available) to calculate the timestamp. Since PHP 5.1.0 there are easier ways to define the timezone that is used across all date/time functions. That process is explained in the date_default_timezone_get() function page.

Parameters

time: A date/time string. Valid formats are explained in Date and Time Formats.
now: The timestamp which is used as a base for the calculation of relative dates.

Return Values

Returns a timestamp on success, FALSE otherwise. Previous to PHP 5.1.0, this function would return -1 on failure.

Errors/Exceptions

Every call to a date/time function will generate a E_NOTICE if the time zone is not valid, and/or a E_STRICT or E_WARNING message if using the system settings or the TZ environment variable. See also date_default_timezone_set()

Changelog

Version	Description
5.3.0	Prior to PHP 5.3.0, 24:00 was not a valid format and strtotime() returned `FALSE`.
5.2.7	In PHP 5 prior to 5.2.7, requesting a given occurrence of a given weekday in a month where that weekday was the first day of the month would incorrectly add one week to the returned timestamp. This has been corrected in 5.2.7 and later versions.
5.1.0	Now returns `FALSE` on failure, instead of -1.
5.1.0	Now issues the `E_STRICT` and `E_NOTICE` time zone errors.
5.0.2	In PHP 5 up to 5.0.2, "now" and other relative times are wrongly computed from today's midnight. This differs from other versions where it is correctly computed from current time.
5.0.0	Microseconds began to be allowed, but they are ignored.
4.4.0	In PHP versions prior to 4.4.0, "next" is incorrectly computed as +2. A typical solution to this is to use "+1".

Examples

Example #1 A strtotime() example

 <?php
echo strtotime("now"), "\n";
echo strtotime("10 September 2000"), "\n";
echo strtotime("+1 day"), "\n";
echo strtotime("+1 week"), "\n";
echo strtotime("+1 week 2 days 4 hours 2 seconds"), "\n";
echo strtotime("next Thursday"), "\n";
echo strtotime("last Monday"), "\n";
?>

Example #2 Checking for failure

 <?php
$str = 'Not Good';

// previous to PHP 5.1.0 you would compare with -1, instead of false
if (($timestamp = strtotime($str)) === false) {
    echo "The string ($str) is bogus";
} else {
    echo "$str == " . date('l dS \o\f F Y h:i:s A', $timestamp);
}
?>

Notes

Note:
If the number of the year is specified in a two digit format, the values between 00-69 are mapped to 2000-2069 and 70-99 to 1970-1999. See the notes below for possible differences on 32bit systems (possible dates might end on 2038-01-19 03:14:07).

Note:
The valid range of a timestamp is typically from Fri, 13 Dec 1901 20:45:54 UTC to Tue, 19 Jan 2038 03:14:07 UTC. (These are the dates that correspond to the minimum and maximum values for a 32-bit signed integer.) Additionally, not all platforms support negative timestamps, therefore your date range may be limited to no earlier than the Unix epoch. This means that e.g. dates prior to Jan 1, 1970 will not work on Windows, some Linux distributions, and a few other operating systems. PHP 5.1.0 and newer versions overcome this limitation though.

Note:
Dates in the m/d/y or d-m-y formats are disambiguated by looking at the separator between the various components: if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed.

To avoid potential ambiguity, it's best to use ISO 8601 (YYYY-MM-DD) dates or DateTime::createFromFormat() when possible.

strtotime