mktime

Get Unix timestamp for a date (PHP 4, PHP 5)
int mktime ( [int hour [, int minute [, int second [, int month [, int day [, int year [, int is_dst]]]]]]] )

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.

Arguments may be left out in order from right to left; any arguments thus omitted will be set to the current value according to the local date and time.

Parameters

hour

The number of the hour.

minute

The number of the minute.

second

The number of seconds past the minute.

month

The number of the month.

day

The number of the day.

year

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. However, before PHP 5.1.0 this range was limited from 1970 to 2038 on some systems (e.g. Windows).

is_dst

This parameter can be set to 1 if the time is during daylight savings time (DST), 0 if it is not, or -1 (the default) if it is unknown whether the time is within daylight savings time or not. If it's unknown, PHP tries to figure it out itself. This can cause unexpected (but not incorrect) results. Some times are invalid if DST is enabled on the system PHP is running on or is_dst is set to 1. If DST is enabled in e.g. 2:00, all times between 2:00 and 3:00 are invalid and mktime() returns an undefined (usually negative) value. Some systems (e.g. Solaris 8) enable DST at midnight so time 0:30 of the day when DST is enabled is evaluated as 23:30 of the previous day.

Note:

As of PHP 5.1.0, this parameter became deprecated. As a result, the new timezone handling features should be used instead.

Return Values

mktime() returns the Unix timestamp of the arguments given. If the arguments are invalid, the function returns FALSE (before PHP 5.1 it returned -1).

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 message if using the system settings or the TZ environment variable. See also date_default_timezone_set()

ChangeLog

Version	Description
3.0.10	Added `is_dst` parameter
5.1.0	The `is_dst` parameter became deprecated. Made the function return `FALSE` on error, instead of `-1`. Fixed the function to accept the year, month and day to be all passed as zero.
5.1.0	Now issues the `E_STRICT` and `E_NOTICE` time zone errors.

Examples

Example 458. mktime() example

mktime() is useful for doing date arithmetic and validation, as it will automatically calculate the correct value for out-of-range input. For example, each of the following lines produces the string "Jan-01-1998".

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<?php
echo date("M-d-Y", mktime(0, 0, 0, 12, 32, 1997));

echo date("M-d-Y", mktime(0, 0, 0, 13, 1, 1997));

echo date("M-d-Y", mktime(0, 0, 0, 1, 1, 1998));

echo date("M-d-Y", mktime(0, 0, 0, 1, 1, 98));
?>

Example 459. Last day of next month

The last day of any given month can be expressed as the "0" day of the next month, not the -1 day. Both of the following examples will produce the string "The last day in Feb 2000 is: 29".

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<?php

$lastday = mktime(0, 0, 0, 3, 0, 2000);

echo strftime("Last day in Feb 2000 is: %d", $lastday);
$lastday = mktime(0, 0, 0, 4, -31, 2000);

echo strftime("Last day in Feb 2000 is: %d", $lastday);
?>

Notes

Caution:

Before PHP 5.1.0, negative timestamps were not supported under any known version of Windows and some other systems as well. Therefore the range of valid years was limited to 1970 through 2038.

See Also

gmmktime()

date()

time()

Related Examples ( Source code ) » mktime

Code Examples / Notes » mktime

You cannot simply subtract or add month VARs using mktime to obtain previous or next months as suggested in previous user comments (at least not with a DD > 28 anyway). If the date is 03-31-2007, the following yeilds March as a previous month. Not what you wanted. <?php $dateMinusOneMonth = mktime(0, 0, 0, (3-1), 31, 2007 ); $lastmonth = date("n | F", $dateMinusOneMonth); echo $lastmonth; //---> 3 | March ?> mktime correctly gives you back the 3rd of March if you subtract 1 month from March 31 (there are only 28 days in Feb 07). If you are just looking to do month and year arithmetic using mktime, you can use general days like 1 or 28 to do stuff like this: <?php $d_daysinmonth = date('t', mktime(0,0,0,$myMonth,1,$myYear)); // how many days in month $d_year = date('Y', mktime(0,0,0,$myMonth,1,$myYear)); // year $d_isleapyear = date('L', mktime(0,0,0,$myMonth,1,$myYear)); // is YYYY a leapyear? $d_firstdow = date('w', mktime(0,0,0,$myMonth,'1',$myYear)); // FIRST falls on what day of week (0-6) $d_firstname = date('l', mktime(0,0,0,$myMonth,'1',$myYear)); // FIRST falls on what day of week Full Name $d_month = date('n', mktime(0,0,0,$myMonth,28,$myYear)); // month of year (1-12) $d_monthname = date('F', mktime(0,0,0,$myMonth,28,$myYear)); // Month Long name (July) $d_month_previous = date('n', mktime(0,0,0,($myMonth-1),28,$myYear)); // PREVIOUS month of year (1-12) $d_monthname_previous = date('F', mktime(0,0,0,($myMonth-1),28,$myYear)); // PREVIOUS Month Long name (July) $d_month_next = date('n', mktime(0,0,0,($myMonth+1),28,$myYear)); // NEXT month of year (1-12) $d_monthname_next = date('F', mktime(0,0,0,($myMonth+1),28,$myYear)); // NEXT Month Long name (July) $d_year_previous = date('Y', mktime(0,0,0,$myMonth,28,($myYear-1))); // PREVIOUS year $d_year_next = date('Y', mktime(0,0,0,$myMonth,28,($myYear+1))); // NEXT year $d_weeksleft = (52 - $d_weekofyear); // how many weeks left in year $d_daysinyear = $d_isleapyear ? 366 : 365; // set correct days in year for leap years $d_daysleft = ($d_daysinyear - $d_dayofyear); // how many days left in year ?>

Very often we are faced with the problem of adjusting ourself to local time where application is running rather than running our application at server time. Now we have a way to do that by setting TZ variable using putenv() method. But due to the non-availability of standard time zone codes, developers are often faced with the ambiguity of how to implement a non standard time zone(those which are not too popular) I figured a way out myself for this. It uses the information that a particular time zone is n hours ahead or n hours behind standard GMT time zone. here is what i did. <?php $day=15; $month=12; $year=2003; //convert it to unix timestamp $deadline=mktime('','','',$month,$day,$year); //caluculate our time from GMT time $hour=gmdate('H'); $min=gmdate('i'); $sec=gmdate('s'); $month=gmdate('n'); $day=gmdate('d'); $year=gmdate('Y'); $stamp=mktime ($hour,$min,$sec,$month,$day,$year); // technique is to convert the GMT date & time to unix stamp, then convert time zone //specific information like add 5 hours or subtract 5 hours to seconds,(consider day //light saving here), and add/subtract it to the unix time stamp and then convert //it back to date using date function if needed or perform operations needed on the // time stamp //subtract 6/n hours from GMT time (Central standard time/CST) //vary this part to whatever time zone you are at $do=6*60*60; $lstamp=$stamp-$do; echo("Today(local date/Central):".date('h:i:s d/n/Y',$lstamp)." "); $left=$deadline-$lstamp; $days_left=floor($left/(24 * 60 * 60)); $hours_left=floor($left/(60 * 60 )); echo " Days Left: $days_left "; echo " Hours Left(approx): $hours_left "; ?> Change the $do variable to whatever seconds you are different from GMT and add or subtract accordingly to generate $lstamp. This would solve your time zone problems. Happy Coding, Suneel Kanuri

There are several warnings here about using mktime() to determine a date difference because of daylight savings time. However, nobody seems to have mentioned the other obvious problem, which is leap years. Leap years mean that any effort to use mktime() and time() to determine the age (positive or negative) of some timestamp in years will be flawed. There are some years that are 366 days long, therefore you cannot say that there is a set number of seconds per year. Timestamps are good for determining *real* time, which is not the same thing as *human calendar* time. The Gregorian calendar is only an approximation of real time, which is tweaked with daylight savings time and leap years to make it conform more to humans' expectations of how time should or ought to work. Timestamps are not tweaked and therefore are the only authoritative way of recording in computers a proper order of succession of events, but they cannot be integrated with a Gregorian system unless you take both leap years and DST into account. Otherwise, you may get the wrong number of years when you are approaching a value of exactly X years. As for PHP, you could still use timestamps as a way of determining age if you took into account not only DST but also whether or not each year is a leap year and adjusted your calculations accordingly. However, this could become messy and inefficient. There is an alternative approach to calculating days given the day, month and year of the dates to be compared. Compare the years first, and then compare the month and day - if the month and day have already passed (or, if you like, if they match the current month and day), then add 1 to the total for the years. This solution works because it stays within the Gregorian system and doesn't venture into the world of timestamps. Here is a good discussion of this issue: http://forums.devshed.com/php-development-5/ need-to-get-the-age-between-dob- and-today-29925.html?&highlight=age+leap [the above link was too long; combine the three lines to get the URL] There is also the issue of leap seconds, but this will only arise if you literally need to get the *exact* age in seconds. In that case, of course, you would also need to verify that your timestamps are exactly correct and are not delayed by script processing time, plus you would need to determine whether your system conforms to UTC, etc. I expect this will hardly be an issue for anybody using PHP, however if you are interested there is an article on this issue on Wikipedia: http://en.wikipedia.org/wiki/Leap_second

here's a function to generate a timestamp from a certain date by using patterns: <?php function str2time($strStr, $strPattern = null) { // an array of the valide date characters, see: http://php.net/date#AEN21898 $arrCharacters = array( 'd', // day 'm', // month 'y', // year, 2 digits 'Y', // year, 4 digits 'H', // hours 'i', // minutes 's' // seconds ); // transform the characters array to a string $strCharacters = implode('', $arrCharacters); // splits up the pattern by the date characters to get an array of the delimiters between the date characters $arrDelimiters = preg_split('~['.$strCharacters.']~', $strPattern); // transform the delimiters array to a string $strDelimiters = quotemeta(implode('', array_unique($arrDelimiters))); // splits up the date by the delimiters to get an array of the declaration $arrStr = preg_split('~['.$strDelimiters.']~', $strStr); // splits up the pattern by the delimiters to get an array of the used characters $arrPattern = preg_split('~['.$strDelimiters.']~', $strPattern); // if the numbers of the two array are not the same, return false, because the cannot belong together if (count($arrStr) !== count($arrPattern)) { return false; } // creates a new array which has the keys from the $arrPattern array and the values from the $arrStr array $arrTime = array(); for ($i = 0;$i < count($arrStr);$i++) { $arrTime[$arrPattern[$i]] = $arrStr[$i]; } // gernerates a 4 digit year declaration of a 2 digit one by using the current year if (isset($arrTime['y']) && !isset($arrTime['Y'])) { $arrTime['Y'] = substr(date('Y'), 0, 2) . $arrTime['y']; } // if a declaration is empty, it will be filled with the current date declaration foreach ($arrCharacters as $strCharacter) { if (empty($arrTime[$strCharacter])) { $arrTime[$strCharacter] = date($strCharacter); } } // checks if the date is a valide date if (!checkdate($arrTime['m'], $arrTime['d'], $arrTime['Y'])) { return false; } // generates the timestamp $intTime = mktime($arrTime['H'], $arrTime['i'], $arrTime['s'], $arrTime['m'], $arrTime['d'], $arrTime['Y']); // returns the timestamp return $intTime; } // example $time = str2time('06-07-08 07:58:02', 'd-m-y H:i:s'); var_dump($time); var_dump(date('d.m.Y H:i:s', $time)); ?>

Here is a quick way to check the a date is valid. I use this when I get users to enter dates via drop downs, which leave open the possibility for impossible dates like 30-Feb-2005 and 31-Jun-2005 etc. This is only necessary as mktime() will accept these invalid dates, which is, in my case, sometimes not the desired handling. <?php function isvaliddate($day, $month, $year) { $day = intval($day); $month = intval($month); $year = intval($year); $time = mktime(0,0,0,$month,$day,$year); if ($day != date("j",$time)) return false; if ($month != date("n",$time)) return false; if ($year != date("Y",$time)) return false; return true; } ?> Note that date("Y",$time) checks the year as a 4 digit year. That line could be replaced as shown below to allow for the 2 digit notation as well. Also the order the arguments need to be specified is day, month, year, because I come from NZ and that is the format we use here. If you prefer another format, for example month, day, year, just change the order of the arguments on the first line. <?php function isvaliddate($day, $month, $year) { $day = intval($day); $month = intval($month); $year = intval($year); $time = mktime(0,0,0,$month,$day,$year); if ($day != date("j",$time)) return false; if ($month != date("n",$time)) return false; if (($year != date("Y",$time)) AND ($year != date("y",$time))) return false; return true; } ?> Hope this helps someone! Cheers, Hayden.

Daylight saving time! Grrrrrrrrrr! (And a minor "Grrr!" for PHP making this less intuitive than it should be). In brief, NEVER add number of seconds, like 60*60*24, but use strtotime("+1 day", $myDate)). Some of the 'simple' functions above for calculating dates will NOT work correctly when a date includes daylight saving time. Shown below is the problem illustrated and a simple solution. EXAMPLE 1: WRONG! I had the following loop, which worked fine all year, until this weekend, when the clocks changed, and it broke! The problem is daylight saving time: // Loop through dates adding 1 days worth of seconds each time $myDate = 1098914400 // October 28th for ($myDate = $fromDate; $myDate <= $toDate; $myDate = $myDate + 60 * 60 * 24) { $printable = strftime("%d-%m-%Y %H:%M:%S", $myDate); echo $printable } "28-10-2004 00:00:00" "29-10-2004 00:00:00" "30-10-2004 00:00:00" "31-10-2004 00:00:00" "31-10-2004 23:00:00" (oops! 31st October repeats and time now 23:00!!) "01-11-2004 23:00:00" "02-11-2004 23:00:00" EXAMPLE 2: CORRECT! $myDate = 1098914400 // October 28th for ($myDate = $fromDate; $myDate <= $toDate; $myDate = strtotime("+1 day", $myDate)) { $printable = strftime("%d-%m-%Y %H:%M:%S", $myDate); echo $printable } "28-10-2004 00:00:00" "29-10-2004 00:00:00" "30-10-2004 00:00:00" "31-10-2004 00:00:00" "01-11-2004 00:00:00" "02-11-2004 00:00:00"