PHP gregoriantojd() Function

The PHP gregoriantojd() function converts a Gregorian date to Julian Day Count. The valid range for the Gregorian calendar is from November 25, 4714 B.C. to at least December 31, 9999 A.D.

Although this function can handle dates all the way back to 4714 B.C., such use may not be meaningful. The Gregorian calendar was not instituted until October 15, 1582 (or October 5, 1582 in the Julian calendar). Some countries did not accept it until much later. For example, Britain converted in 1752, The USSR in 1918 and Greece in 1923. Most European countries used the Julian calendar prior to the Gregorian.

Syntax

gregoriantojd(month, day, year)

Parameters

Return Value

Returns the Julian Day count for the given Gregorian date. Dates outside the valid range return 0.

Exceptions

NA.

Example:

The example below shows the usage of gregoriantojd() function.

<?php
//converting a Gregorian date
//to Julian integer 
$jd = gregoriantojd(10, 2, 2015);
  
//displaying the Julian day integer 
echo "The Julian day integer is: $jd \n";
  
//converting the Julian day integer 
//to Gregorian date
$date = jdtogregorian($jd);
  
//displaying the Gregorian date
echo "The Gregorian date is: $date \n"; 
?>

The output of the above code will be:

The Julian day integer is: 2457298 
The Gregorian date is: 10/2/2015 

Example: Overflow behavior

Consider one more example to see the overflow behavior of this function.

<?php
//converting an invalid Gregorian 
//date to Julian integer 
$jd = gregoriantojd(15, 2, 2018);
  
//prints 0 as month is out of range 
echo "The Julian day integer is: $jd \n";
  
//converting the Julian day integer 
//to Gregorian date
$date = jdtogregorian($jd);
  
//prints 0/0/0 as Gregorian 
//month is out of range
echo "The Gregorian date is: $date \n"; 
?>

The output of the above code will be:

The Julian day integer is: 0 
The Gregorian date is: 0/0/0