How to Convert Jewish Date to Julian Date in PHP

As a developer, you might come across a situation where you need to convert a Jewish date to a Julian date. This can be a challenging task as the Jewish calendar follows a different system compared to the Gregorian calendar that we use today. Fortunately, PHP provides us with a set of functions that can help us achieve this.

Understanding the Jewish Calendar

Before we dive into the conversion process, let's take a moment to understand the Jewish calendar. The Jewish calendar is a lunisolar calendar, which means it is based on both the cycles of the moon and the sun. It consists of 12 lunar months of 29 or 30 days, with an extra month added in leap years to keep the calendar in sync with the solar year. The months are named according to Babylonian tradition and are based on the phases of the moon.

Unlike the Gregorian calendar, which starts from the year of Jesus' birth, the Jewish calendar begins from the creation of the world, which is believed to have occurred in 3761 BCE. This means that the current Jewish year, 5783, corresponds to the number of years that have passed since the creation of the world.

Converting Jewish Date to Julian Date

To convert a Jewish date to a Julian date, we first need to calculate the number of days that have passed since the start of the Jewish calendar. We can do this using the jewishtojd() function provided by PHP.

The jewishtojd() function takes three parameters: the Jewish month, day, and year. It returns the Julian day number, which is the number of days since noon on January 1, 4713 BCE, in the Julian calendar.

Here's an example code snippet that demonstrates how to use the jewishtojd() function:


$jewish_month = 6;
$jewish_day = 5;
$jewish_year = 5783;

$julian_day_number = jewishtojd($jewish_month, $jewish_day, $jewish_year);

echo "The Julian day number is: " . $julian_day_number;

The above code will output the Julian day number for the Jewish date of 6 Sivan 5783.


In this article, we learned how to convert a Jewish date to a Julian date in PHP. We explored the Jewish calendar and its unique features, such as its lunisolar system and its starting point from the creation of the world. We also used the jewishtojd() function to perform the conversion and demonstrated how to use it with a code snippet.

By following these steps, you can easily convert Jewish dates to Julian dates in your PHP applications.

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