cal_to_jd: getting Julian day count

$jd = cal_to_jd(CAL_GREGORIAN, 9, 14, 2026);
echo $jd;

$day = cal_to_jd(CAL_GREGORIAN,2,2,2103);
echo $day;

cal_to_jd($calendar, $month, $day, $year)

Example: Converting Gregorian Date to Julian Day

$jd = cal_to_jd(CAL_GREGORIAN, 10, 8, 2023);
echo "Julian Day: " . $jd;  // Output: Julian Day: 2460219

Validate a Gregorian date before conversion

cal_to_jd() returns a Julian Day count; it is not a Gregorian date validator. When user input represents a Gregorian date, validate it with checkdate() first.

$month = 2;
$day = 30;
$year = 2023;

if (checkdate($month, $day, $year)) {
    $jd = cal_to_jd(CAL_GREGORIAN, $month, $day, $year);
    echo "Julian Day: " . $jd;
} else {
    echo "Invalid Gregorian date";
}

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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