mktime()

mktime() — Get Unix timestamp for a date.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

Returns the Unix timestamp corresponding to the arguments given. This timestamp is a long integer containing the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified.

Signature

mktime(int $hour, ?int $minute = null, ?int $second = null, ?int $month = null, ?int $day = null, ?int $year = null): int|false

Parameters

Parameter	Type	What it takes
$hour	int	The number of the hour relative to the start of the day determined by month, day and year. Negative values reference the hour before midnight of the day in question. Values greater than 23 reference the appropriate hour in the following day(s).
$minute	?int	The number of the minute relative to the start of the hour. Negative values reference the minute in the previous hour. Values greater than 59 reference the appropriate minute in the following hour(s).
$second	?int	The number of seconds relative to the start of the minute. Negative values reference the second in the previous minute. Values greater than 59 reference the appropriate second in the following minute(s).
$month	?int	The number of the month relative to the end of the previous year. Values 1 to 12 reference the normal calendar months of the year in question. Values less than 1 (including negative values) reference the months in the previous year in reverse order, so 0 is December, -1 is November, etc. Values greater than 12 reference the appropriate month in the following year(s).
$day	?int	The number of the day relative to the end of the previous month. Values 1 to 28, 29, 30 or 31 (depending upon the month) reference the normal days in the relevant month. Values less than 1 (including negative values) reference the days in the previous month, so 0 is the last day of the previous month, -1 is the day before that, etc. Values greater than the number of days in the relevant month reference the ...
$year	?int	The number of the year, may be a two or four digit value, with values between 0-69 mapping to 2000-2069 and 70-100 to 1970-2000. On systems where time_t is a 32bit signed integer, as most common today, the valid range for year is somewhere between 1901 and 2038.

Return value

mktime() returns the Unix timestamp of the arguments given, or false if the timestamp doesn't fit in a PHP integer.

Example

A runnable snippet:

// Set the default timezone to use. date_default_timezone_set('UTC'); // Prints: July 1, 2000 is on a Saturday echo "July 1, 2000 is on a " . date("l", mktime(0, 0, 0, 7, 1, 2000)) . "\n"; // Prints something like: 2006-04-05T01:02:03+00:00 echo date('c', mktime(1, 2, 3, 4, 5, 2006)) . "\n";

Output:

July 1, 2000 is on a Saturday 2006-04-05T01:02:03+00:00

Changelog

Version	Change
8.0.0	hour is no longer optional. If you need a Unix timestamp, use time().
8.0.0	minute, second, month, day and year are nullable now.