PHP 5.5.15 is released

cal_days_in_month

(PHP 4 >= 4.1.0, PHP 5)

cal_days_in_monthReturn the number of days in a month for a given year and calendar

Description

int cal_days_in_month ( int $calendar , int $month , int $year )

This function will return the number of days in the month of year for the specified calendar.

Parameters

calendar

Calendar to use for calculation

month

Month in the selected calendar

year

Year in the selected calendar

Return Values

The length in days of the selected month in the given calendar

Examples

Example #1 cal_days_in_month() example

<?php
$num 
cal_days_in_month(CAL_GREGORIAN82003); // 31
echo "There was $num days in August 2003";
?>

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User Contributed Notes 10 notes

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25
brian at b5media dot com
6 years ago
Remember if you just want the days in the current month, use the date function:
$days = date("t");
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7
dbindel at austin dot rr dot com
10 years ago
Here's a one-line function I just wrote to find the numbers of days in a month that doesn't depend on any other functions.

The reason I made this is because I just found out I forgot to compile PHP with support for calendars, and a class I'm writing for my website's open source section was broken. So rather than recompiling PHP (which I will get around to tomorrow I guess), I just wrote this function which should work just as well, and will always work without the requirement of PHP's calendar extension or any other PHP functions for that matter.

I learned the days of the month using the old knuckle & inbetween knuckle method, so that should explain the mod 7 part. :)

<?php
/*
* days_in_month($month, $year)
* Returns the number of days in a given month and year, taking into account leap years.
*
* $month: numeric month (integers 1-12)
* $year: numeric year (any integer)
*
* Prec: $month is an integer between 1 and 12, inclusive, and $year is an integer.
* Post: none
*/
// corrected by ben at sparkyb dot net
function days_in_month($month, $year)
{
// calculate number of days in a month
return $month == 2 ? ($year % 4 ? 28 : ($year % 100 ? 29 : ($year % 400 ? 28 : 29))) : (($month - 1) % 7 % 2 ? 30 : 31);
}
?>

Enjoy,
David Bindel
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1
geko45pj at yahoo dot com
7 years ago
<?php
# PHP Calendar (version 2.3), written by Keith Devens

function generate_calendar($year, $month, $days = array(), $day_name_length = 3, $month_href = NULL, $first_day = 0, $pn = array()){
   
$first_of_month = gmmktime(0,0,0,$month,1,$year);

   
#remember that mktime will automatically correct if invalid dates are entered
    # for instance, mktime(0,0,0,12,32,1997) will be the date for Jan 1, 1998
    # this provides a built in "rounding" feature to generate_calendar()

   
$day_names = array(); #generate all the day names according to the current locale
   
for($n=0,$t=(3+$first_day)*86400; $n<7; $n++,$t+=86400) #January 4, 1970 was a Sunday
       
$day_names[$n] = ucfirst(gmstrftime('%A',$t)); #%A means full textual day name

   
list($month, $year, $month_name, $weekday) = explode(',',gmstrftime('%m,%Y,%B,%w',$first_of_month));
   
$weekday = ($weekday + 7 - $first_day) % 7; #adjust for $first_day
   
$title   = htmlentities(ucfirst($month_name)).'&nbsp;'.$year#note that some locales don't capitalize month and day names

    #Begin calendar. Uses a real <caption>. See http://diveintomark.org/archives/2002/07/03
   
@list($p, $pl) = each($pn); @list($n, $nl) = each($pn); #previous and next links, if applicable
   
if($p) $p = '<span class="calendar-prev">'.($pl ? '<a href="'.htmlspecialchars($pl).'">'.$p.'</a>' : $p).'</span>&nbsp;';
    if(
$n) $n = '&nbsp;<span class="calendar-next">'.($nl ? '<a href="'.htmlspecialchars($nl).'">'.$n.'</a>' : $n).'</span>';
   
$calendar = '<table class="calendar">'."\n".
       
'<caption class="calendar-month">'.$p.($month_href ? '<a href="'.htmlspecialchars($month_href).'">'.$title.'</a>' : $title).$n."</caption>\n<tr>";

    if(
$day_name_length){ #if the day names should be shown ($day_name_length > 0)
        #if day_name_length is >3, the full name of the day will be printed
       
foreach($day_names as $d)
           
$calendar .= '<th abbr="'.htmlentities($d).'">'.htmlentities($day_name_length < 4 ? substr($d,0,$day_name_length) : $d).'</th>';
       
$calendar .= "</tr>\n<tr>";
    }

    if(
$weekday > 0) $calendar .= '<td colspan="'.$weekday.'">&nbsp;</td>'; #initial 'empty' days
   
for($day=1,$days_in_month=gmdate('t',$first_of_month); $day<=$days_in_month; $day++,$weekday++){
        if(
$weekday == 7){
           
$weekday   = 0; #start a new week
           
$calendar .= "</tr>\n<tr>";
        }
        if(isset(
$days[$day]) and is_array($days[$day])){
            @list(
$link, $classes, $content) = $days[$day];
            if(
is_null($content))  $content  = $day;
           
$calendar .= '<td'.($classes ? ' class="'.htmlspecialchars($classes).'">' : '>').
                (
$link ? '<a href="'.htmlspecialchars($link).'">'.$content.'</a>' : $content).'</td>';
        }
        else
$calendar .= "<td>$day</td>";
    }
    if(
$weekday != 7) $calendar .= '<td colspan="'.(7-$weekday).'">&nbsp;</td>'; #remaining "empty" days

   
return $calendar."</tr>\n</table>\n";
}
echo
generate_calendar(2010, 12, 16,3,NULL,0,15, $first_of_month, $day_names, $day_names[$n]);
#echo generate_calendar($year, $month, $days,$day_name_length,$month_href,$first_day,$pn);
?>
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1
Anonymous
2 years ago
You can also use the date() function to get the number of days in a month. You can also pass the 2nd param strtotime() and specify a specific date:

date('t');
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1
deva dot ananth at gmail dot com
3 years ago
Function  for calculation number of days until birthday:

<?php
function daysLeftForBirthday($devabirthdate)
{
   
/* input birthday date format -> Y-m-d */
   
list($y, $m, $d) = explode('-',$devabirthdate);
   
$nowdate = mktime(0, 0, 0, date("m"), date("d"), date("Y"));
   
$nextbirthday = mktime(0,0,0,$m, $d, date("Y"));

    if (
$nextbirthday<$nowdate)
       
$nextbirthday=$nextbirthday+(60*60*24*365);

   
$daycount=intval(($nextbirthday-$nowdate)/(60*60*24));

    return
$daycount;
}
?>
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1
jeffbeall at comcast dot net
10 years ago
This will work great in future dates but will give the wrong answer for dates before 1550 (approx) when leap year was introduced and the calendar lost a year or two.
Sorry now to be more specific it has been a while sine I had to account for those later dates and had to take that into account but just a heads up for others to watch out.
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2
adam.pippin at ohmedia.ca
3 years ago
Forgot to compile the calendar plugin in... Wrote a workaround while I waited for it to compile. It only supports the Gregorian calendar.

<?php
if (!function_exists('cal_days_in_month'))
{
    function
cal_days_in_month($calendar, $month, $year)
    {
        return
date('t', mktime(0, 0, 0, $month, 1, $year));
    }
}
if (!
defined('CAL_GREGORIAN'))
   
define('CAL_GREGORIAN', 1);
?>
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1
p2409 at hotmail dot com
8 months ago
If you have a DateTime variable you want to find the number of days in the month for, you can simply use $dt->format and the format specifiers 'm' and 'Y' to get the month digit, and year to use with cal_days_in_month eg.

function DaysInMonth($dt) {
    $m =  $dt->format('m');
    $y =  $dt->format('Y');
    $numDays = cal_days_in_month (CAL_GREGORIAN, $m,$y);
    return $numDays;
}
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0
asifsajjad at gmail dot com
11 months ago
count specific days in a month like how many satureday in a monday or how many mondays in a month
<?php

function my_cal_days_in_month($year,$month,$calday="1"){ //0 Sunday, 1 Monday, 2 Tue , 3 Wed , 4. Thu , 5. Fri , 6. Sat
    // calculate total number of occurance in this month
   
$num = cal_days_in_month(CAL_GREGORIAN, $month, $year); // days in month
   
$dayofweek = date( "w", mktime(0, 0, 0, $month, 1, $year));    
   
$adddays=0;
    if(
$calday > $dayofweek )
           
$adddays=1 + $calday - $dayofweek;
    else if(
$calday < $dayofweek )
           
$adddays=1 + 7 + ($calday - $dayofweek );
               
   
$remainingdays=$num-$adddays;
   
$leavesnum=1+intval($remainingdays / 7);
    return    
$leavesnum;
}

$year=2013;
$month=7;
$day=6;
echo
my_cal_days_in_month($year,$month,$day);
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0
paul (at) bughunt3r.com
10 years ago
Here is a nifty function to return the date for easter for ranges beyond 2037 or before 1970.

<?php
   
function str_easter_date ($year) {
       
$days = easter_days ($year);
       
$days_in_march = cal_days_in_month (CAL_GREGORIAN, 3, $year);
        if ((
$days + 21) < $days_in_march) {
           
$month = "March";
           
$date = $days + 21;
        } else {
           
$month = "April";
           
$date = ($days + 21) - $days_in_march;
        }
       
        return
"$month $date, $year";
    }
?>
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