php get first day of the month code example

Example 1: get first day of current month php

<?php
    // First day of this month
    $d = new DateTime('first day of this month');
    echo $d->format('jS, F Y');
?>

Example 2: get next month first day php

$config_month  = 1;
$config_day = 1;

$new_expiry_date = date('Y-m-d', mktime(0, 0, 0, date('m') + $config_month, 1 + $config_day, date('Y')));

Example 3: get day of month php

// get day of month php
// Method 1; some server not work, I had check php 7.3.24 not worked, php 7.3.8 worked
cal_days_in_month(CAL_GREGORIAN, $month, $year)
echo (cal_days_in_month(CAL_GREGORIAN, 2, 2020)); // => 29

// Method 2;
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);
}

// Method 3;
echo (date('t', strtotime('2020-02-1')));	// 29